Security Configuration Guide: Zone-Based Policy Firewall, Cisco IOS XE Release 3S
IPv6 Firewall Support for Prevention of Distributed Denial of Service Attacks and Resource Management
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Contents

IPv6 Firewall Support for Prevention of Distributed Denial of Service Attacks and Resource Management

IPv6 zone-based firewalls support the Protection of Distributed Denial of Service Attacks and the Firewall Resource Management features.

The Protection Against Distributed Denial of Service Attacks feature provides protection from Denial of Service (DoS) attacks at the global level (for all firewall sessions) and at the VPN routing and forwarding (VRF) level. With the Protection Against Distributed Denial of Service Attacks feature, you can configure the aggressive aging of firewall sessions, event rate monitoring of firewall sessions, half-opened connections limit, and global TCP synchronization (SYN) cookie protection to prevent distributed DoS attacks.

The Firewall Resource Management feature limits the number of VPN Routing and Forwarding (VRF) and global firewall sessions that are configured on a device.

This module describes how to configure the Protection of Distributed Denial of Service Attacks and the Firewall Resource Management features.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Restrictions for IPv6 Firewall Support for Protection Against Distributed Denial of Service Attacks and Resource Management

The following restriction applies to the Firewall Resource Management feature:

  • After you configure the global-level or the virtual routing and forwarding (VRF)-level session limit and reconfigure the session limit, if the global-level or the VRF-level session limit is below the initially configured session count, no new session is added; however, no current session is dropped.

Information About IPv6 Firewall Support for Prevention of Distributed Denial of Service Attacks and Resource Management

Aggressive Aging of Firewall Sessions

The Aggressive Aging feature provides the firewall the capability of aggressively aging out sessions to make room for new sessions, thereby protecting the firewall session database from filling. The firewall protects its resources by removing idle sessions. The Aggressive Aging feature allows firewall sessions to exist for a shorter period of time defined by a timer called aging-out time.

The Aggressive Aging feature includes thresholds to define the start and end of the aggressive aging period—high and low watermarks. The aggressive aging period starts when the session table crosses the high watermark and ends when it falls below the low watermark. During the aggressive aging period, sessions will exist for a shorter period of time that you have configured by using the aging-out time. If an attacker initiates sessions at a rate that is faster than the rate at which the firewall terminates sessions, all resources that are allocated for creating sessions are used and all new connections are rejected. To prevent such attacks, you can configure the Aggressive Aging feature to aggressively age out sessions. This feature is disabled by default.

You can configure aggressive aging for half-opened sessions and total sessions at the box level (box refers to the entire firewall session table) and the virtual routing and forwarding (VRF) level. If you have configured this feature for total sessions, all sessions that consume firewall session resources are taken into account. Total sessions comprise established sessions, half-opened sessions, and sessions in the imprecise session database. (A TCP session that has not yet reached the established state is called a half-opened session.)

A firewall has two session databases: the session database and the imprecise session database. The session database contains sessions with 5-tuple (the source IP address, the destination IP address, the source port, the destination port, and the protocol). A tuple is an ordered list of elements. The imprecise session database contains sessions with fewer than 5-tuple (missing IP addresses, port numbers, and so on). In the case of aggressive aging for half-opened sessions, only half-opened sessions are considered.

You can configure an aggressive aging-out time for Internet Control Message Protocol (ICMP), TCP, and UDP firewall sessions. The aging-out time is set by default to the idle time.

Event Rate Monitoring Feature

The Event Rate Monitoring feature monitors the rate of predefined events in a zone. The Event Rate Monitoring feature includes basic threat detection, which is the ability of a security device to detect possible threats, anomalies, and attacks to resources inside the firewall and to take action against them. You can configure a basic threat detection rate for events. When the incoming rate of a certain type of event exceeds the configured threat detection rate, event rate monitoring considers this event as a threat and takes action to stop the threat. Threat detection inspects events only on the ingress zone (if the Event Rate Monitoring feature is enabled on the ingress zone).

The network administrator is informed about the potential threats via an alert message (syslog or high-speed logger [HSL]) and can take actions such as detecting the attack vector, detecting the zone from which the attack is coming, or configuring devices in the network to block certain behaviors or traffic.

The Event Rate Monitoring feature monitors the following types of events:

  • Firewall drops due to basic firewall checks failure—This can include zone or zone-pair check failures, or firewall policies configured with the drop action, and so on.
  • Firewall drops due to Layer 4 inspection failure—This can include TCP inspections that have failed because the first TCP packet is not a synchronization (SYN) packet.
  • TCP SYN cookie attack—This can include counting the number of SYN packets that are dropped and the number of SYN cookies that are sent as a spoofing attack.

The Event Rate Monitoring feature monitors the average rate and the burst rate of different events. Each event type has a rate object that is controlled by an associated rate that has a configurable parameter set (the average threshold, the burst threshold, and a time period). The time period is divided into time slots; each time slot is 1/30th of the time period.

The average rate is calculated for every event type. Each rate object holds 30 completed sampling values plus one value to hold the current ongoing sampling period. The current sampling value replaces the oldest calculated value and the average is recalculated. The average rate is calculated during every time period. If the average rate exceeds the average threshold, the Event Rate Monitoring feature will consider this as a possible threat, update the statistics, and inform the network administrator.

The burst rate is implemented by using the token bucket algorithm. For each time slot, the token bucket is filled with tokens. For each event that occurs (of a specific event type), a token is removed from the bucket. An empty bucket means that the burst threshold is reached, and the administrator receives an alarm through the syslog or HSL. You can view the threat detection statistics and learn about possible threats to various events in the zone from the output of the show policy-firewall stats zone command.

You must first enable basic threat detection by using the threat-detection basic-threat command. Once basic threat detection is configured, you can configure the threat detection rate. To configure the threat detection rate, use the threat-detection rate command.

The following table describes the basic threat detection default settings that are applicable if the Event Rate Monitoring feature is enabled.

Table 1 Basic Threat Detection Default Settings

Packet Drop Reason

Threat Detection Settings

Basic firewall drops

average-rate 400 packets per second (pps)

burst-rate 1600 pps

rate-interval 600 seconds

Inspection-based firewall drops

average-rate 400 pps

burst-rate 1600 pps

rate-interval 600 seconds

SYN attack firewall drops

average-rate 100 pps

burst-rate 200 pps

rate-interval 600 seconds

Half-Opened Connections Limit

The firewall session table supports the limiting of half-opened firewall connections. Limiting the number of half-opened sessions will defend the firewall against attacks that might fill the firewall session table at the per-box level or at the virtual routing and forwarding (VRF) level with half-opened sessions and prevent sessions from being established. The half-opened connection limit can be configured for Layer 4 protocols, Internet Control Message Protocol (ICMP), TCP, and UDP. The limit set to the number of UDP half-opened sessions will not affect the TCP or ICMP half-opened sessions. When the configured half-opened session limit is exceeded, all new sessions are rejected and a log message is generated, either in syslog or in the high-speed logger (HSL).

The following sessions are considered as half-opened sessions:
  • TCP sessions that have not completed the three-way handshake.
  • UDP sessions that have only one packet detected in the UDP flow.
  • ICMP sessions that do not receive a reply to the ICMP echo request or the ICMP time-stamp request.

TCP SYN-Flood Attacks

You can configure the global TCP SYN-flood limit to limit SYN flood attacks. TCP SYN-flooding attacks are a type of denial of service (DoS) attack. When the configured TCP SYN-flood limit is reached, the firewall verifies the source of sessions before creating more sessions. Usually, TCP SYN packets are sent to a targeted end host or a range of subnet addresses behind the firewall. These TCP SYN packets have spoofed source IP addresses. A spoofing attack is when a person or program tries to use false data to gain access to resources in a network. TCP SYN flooding can take up all resources on a firewall or an end host, thereby causing denial of service to legitimate traffic. You can configure TCP SYN-flood protection at the VRF level and the zone level.

SYN flood attacks are divided into two types:
  • Host flood—SYN flood packets are sent to a single host intending to utilize all resources on that host.
  • Firewall session table flood—SYN flood packets are sent to a range of addresses behind the firewall, with the intention of exhausting the session table resources on the firewall, thereby denying resources to the legitimate traffic going through the firewall.

Firewall Resource Management

Resource Management limits the level of usage of shared resources on a device. Shared resources on a device include:

  • Bandwidth
  • Connection states
  • Memory usage (per table)
  • Number of sessions or calls
  • Packets per second
  • Ternary content addressable memory (TCAM) entries

The Firewall Resource Management feature extends the zone-based firewall resource management from the class level to the VRF level and the global level. Class-level resource management provides resource protection for firewall sessions at a class level. For example, parameters such as the maximum session limit, the session rate limit, and the incomplete session limit protect firewall resources (for example, chunk memory) and keep these resources from being used up by a single class.

When virtual routing and forwarding (VRF) instances share the same policy, a firewall session setup request from one VRF instance can make the total session count reach the maximum limit. When one VRF consumes the maximum amount of resources on a device, it becomes difficult for other VRF instances to share device resources. To limit the number of VRF firewall sessions, you can use the Firewall Resource Management feature.

At the global level, the Firewall Resource Management feature helps limit the usage of resources at the global routing domain by firewall sessions.

Firewall Sessions

Session Definition

At the virtual routing and forwarding (VRF) level, the Firewall Resource Management feature tracks the firewall session count for each VRF instance. At the global level, the firewall resource management tracks the total firewall session count at the global routing domain and not at the device level. In both the VRF and global levels, session count is the sum of opened sessions, half-opened sessions, and sessions in the imprecise firewall session database. A TCP session that has not yet reached the established state is called a half-opened session.

A firewall has two session databases: the session database and the imprecise session database. The session database contains sessions with 5-tuple (source IP address, destination IP address, source port, destination port, and protocol). A tuple is an ordered list of elements. The imprecise session database contains sessions with fewer than 5-tuple (missing IP addresses, port numbers, and so on).

The following rules apply to the configuration of a session limit:

  • The class-level session limit can exceed the global limit.
  • The class-level session limit can exceed its associated VRF session maximum.
  • The sum of the VRF limit, including the global context, can be greater than the hardcoded session limit.

Session Rate

The session rate is the rate at which sessions are established at any given time interval. You can define maximum and minimum session rate limits. When the session rate exceeds the maximum specified rate, the firewall starts rejecting new session setup requests.

From the resource management perspective, setting the maximum and minimum session rate limit helps protect Cisco Packet Processor from being overwhelmed when numerous firewall session setup requests are received.

Incomplete or Half-Opened Sessions

Incomplete sessions are half-opened sessions. Any resource used by an incomplete session is counted, and any growth in the number of incomplete sessions is limited by setting the maximum session limit.

Firewall Resource Management Sessions

The following rules apply to firewall resource management sessions:

  • By default, the session limit for opened and half-opened sessions is unlimited.
  • Opened or half-opened sessions are limited by parameters and counted separately.
  • Opened or half-opened session count includes Internet Control Message Protocol (ICMP), TCP, or UDP sessions.
  • You can limit the number and rate of opened sessions.
  • You can only limit the number of half-opened sessions.

How to Configure IPv6 Firewall Support for Prevention of Distributed Denial of Service Attacks and Resource Management

Configuring an IPv6 Firewall

The steps to configure an IPv4 firewall and an IPv6 firewall are the same. To configure an IPv6 firewall, you must configure the class map in such a way that only an IPv6 address family is matched.

The match protocol command applies to both IPv4 and IPv6 traffic and can be included in either an IPv4 policy or an IPv6 policy.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    vrf-definition vrf-name

    4.    address-family ipv6

    5.    exit-address-family

    6.    exit

    7.    parameter-map type inspect parameter-map-name

    8.    sessions maximum sessions

    9.    exit

    10.    ipv6 unicast-routing

    11.    ip port-map appl-name port port-num list list-name

    12.    ipv6 access-list access-list-name

    13.    permit ipv6 any any

    14.    exit

    15.    class-map type inspect match-all class-map-name

    16.    match access-group name access-group-name

    17.    match protocol protocol-name

    18.    exit

    19.    policy-map type inspect policy-map-name

    20.    class type inspect class-map-name

    21.    inspect [parameter-map-name]

    22.    end


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Device> enable
     
    Enters privileged EXEC mode.
    • Enter your password if prompted.
     
    Step 2 configure terminal


    Example:
    Device# configure terminal
     

    Enters global configuration mode.

     
    Step 3 vrf-definition vrf-name


    Example:
    Device(config)# vrf-definition VRF1
     

    Configures a virtual routing and forwarding (VRF) routing table instance and enters VRF configuration mode.

     
    Step 4 address-family ipv6


    Example:
    Device(config-vrf)# address-family ipv6
     

    Enters VRF address family configuration mode and configures sessions that carry standard IPv6 address prefixes.

     
    Step 5 exit-address-family


    Example:
    Device(config-vrf-af)# exit-address-family
     

    Exits VRF address family configuration mode and enters VRF configuration mode.

     
    Step 6 exit


    Example:
    Device(config-vrf)# exit
     

    Exits VRF configuration mode and enters global configuration mode.

     
    Step 7 parameter-map type inspect parameter-map-name


    Example:
    Device(config)# parameter-map type inspect ipv6-param-map
     

    Enables a global inspect-type parameter map for the firewall to connect thresholds, timeouts, and other parameters that pertain to the inspect action, and enters parameter-map type inspect configuration mode.

     
    Step 8 sessions maximum sessions


    Example:
    Device(config-profile)# sessions maximum 10000
     

    Sets the maximum number of allowed sessions that can exist on a zone pair.

     
    Step 9 exit


    Example:
    Device(config-profile)# exit
     

    Exits parameter-map type inspect configuration mode and enters global configuration mode.

     
    Step 10 ipv6 unicast-routing


    Example:
    Device(config)# ipv6 unicast-routing
     

    Enables the forwarding of IPv6 unicast datagrams.

     
    Step 11 ip port-map appl-name port port-num list list-name


    Example:
    Device(config)# ip port-map ftp port 8090 list ipv6-acl
     

    Establishes a port to application mapping (PAM) by using the IPv6 access control list (ACL).

     
    Step 12 ipv6 access-list access-list-name


    Example:
    Device(config)# ipv6 access-list ipv6-acl
     

    Defines an IPv6 access list and enters IPv6 access list configuration mode.

     
    Step 13 permit ipv6 any any


    Example:
    Device(config-ipv6-acl)# permit ipv6 any any
     

    Sets permit conditions for an IPv6 access list.

     
    Step 14 exit


    Example:
    Device(config-ipv6-acl)# exit
     

    Exits IPv6 access list configuration mode and enters global configuration mode.

     
    Step 15 class-map type inspect match-all class-map-name


    Example:
    Device(config)# class-map type inspect match-all ipv6-class
     

    Creates an application-specific inspect type class map and enters QoS class-map configuration mode.

     
    Step 16 match access-group name access-group-name


    Example:
    Device(config-cmap)# match access-group name ipv6-acl
     

    Configures the match criteria for a class map on the basis of the specified ACL.

     
    Step 17 match protocol protocol-name


    Example:
    Device(config-cmap)# match protocol tcp
     

    Configures a match criterion for a class map on the basis of the specified protocol.

     
    Step 18 exit


    Example:
    Device(config-cmap)# exit
     

    Exits QoS class-map configuration mode and enters global configuration mode.

     
    Step 19 policy-map type inspect policy-map-name


    Example:
    Device(config)# policy-map type inspect ipv6-policy
     

    Creates a protocol-specific inspect type policy map and enters QoS policy-map configuration mode.

     
    Step 20 class type inspect class-map-name


    Example:
    Device(config-pmap)# class type inspect ipv6-class
     

    Specifies the traffic class on which an action is to be performed and enters QoS policy-map class configuration mode.

     
    Step 21 inspect [parameter-map-name]


    Example:
    Device(config-pmap-c)# inspect ipv6-param-map
     

    Enables stateful packet inspection.

     
    Step 22 end


    Example:
    Device(config-pmap-c)# end
     

    Exits QoS policy-map class configuration mode and enters privileged EXEC mode.

     

    Configuring the Aggressive Aging of Firewall Sessions

    You can configure the Aggressive Aging feature for per-box (per-box refers to the entire firewall session table), default-VRF, and per-VRF firewall sessions. Before the Aggressive Aging feature can work, you must configure the aggressive aging and the aging-out time of firewall sessions.

    Perform the following tasks to configure the aggressive aging of firewall sessions.

    Configuring per-Box Aggressive Aging

    Per-box refers to the entire firewall session table. Any configuration that follows the parameter-map type inspect-global command applies to the box.

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    Enter one of the following commands:

      • parameter-map type inspect-global
      • parameter-map type inspect global

      4.    per-box max-incomplete number aggressive-aging high {value low value | percent percent low percent percent}

      5.    per-box aggressive-aging high {value low value | percent percent low percent percent}

      6.    exit

      7.    parameter-map type inspect parameter-map-name

      8.    tcp synwait-time seconds [ageout-time seconds]

      9.    end

      10.    show policy-firewall stats global


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 enable


      Example:
      Device> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.
       
      Step 2configure terminal


      Example:
      Device# configure terminal
       

      Enters global configuration mode.

       
      Step 3Enter one of the following commands:
      • parameter-map type inspect-global
      • parameter-map type inspect global


      Example:
      Device(config)# parameter-map type inspect-global
      Device(config)# parameter-map type inspect global
       
      Configures a global parameter map for connecting thresholds and timeouts and enters parameter-map type inspect configuration mode.
      • Based on your release, the parameter-map type inspect-global and the parameter-map type inspect global commands are supported. You cannot configure both these commands together.
      • Skip Steps 4 and 5 if you configure the parameter-map type inspect-global command.
      Note   

      If you configure the parameter-map type inspect-global command, per-box configurations are not supported because, by default, all per-box configurations apply to all firewall sessions.

       
      Step 4per-box max-incomplete number aggressive-aging high {value low value | percent percent low percent percent}


      Example:
      Device(config-profile)# per-box max-incomplete 2000 aggressive-aging high 1500 low 1200
       

      Configures the maximum limit and the aggressive aging rate for half-opened sessions in the firewall session table.

       
      Step 5per-box aggressive-aging high {value low value | percent percent low percent percent}


      Example:
      Device(config-profile)# per-box aggressive-aging high 1700 low 1300
       

      Configures the aggressive aging limit of total sessions.

       
      Step 6exit


      Example:
      Device(config-profile)# exit
       

      Exits parameter-map type inspect configuration mode and enters global configuration mode.

       
      Step 7parameter-map type inspect parameter-map-name


      Example:
      Device(config)# parameter-map type inspect pmap1
       

      Configures an inspect-type parameter map for connecting thresholds, timeouts, and other parameters pertaining to the inspect action and enters parameter-map type inspect configuration mode.

       
      Step 8tcp synwait-time seconds [ageout-time seconds]


      Example:
      Device(config-profile)# tcp synwait-time 30 ageout-time 10
       

      Specifies how long the software will wait for a TCP session to reach the established state before dropping the session.

      • After aggressive aging is enabled, the SYN wait timer of the oldest TCP connections are reset from the default to the configured ageout time. In this example, instead of waiting for 30 seconds for connections to timeout, the timeout of the oldest TCP connections are set to 10 seconds. Aggressive aging is disabled when the connections drop below the low watermark.
       
      Step 9end


      Example:
      Device(config-profile)# end
       

      Exits parameter-map type inspect configuration mode and enters privileged EXEC mode.

       
      Step 10show policy-firewall stats global


      Example:
      Device# show policy-firewall stats global
       

      Displays global firewall statistics information.

       

      Configuring Aggressive Aging for a Default VRF

      When you configure the max-incomplete aggressive-aging command, it applies to the default VRF.

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    Enters one of the following commands:

        • parameter-map type inspect-global
        • parameter-map type inspect global

        4.    max-incomplete number aggressive-aging high {value low value | percent percent low percent percent}

        5.    session total number [aggressive-aging high {value low value | percent percent low percent percent}]

        6.    exit

        7.    parameter-map type inspect parameter-map-name

        8.    tcp synwait-time seconds [ageout-time seconds]

        9.    end

        10.    show policy-firewall stats vrf global


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 enable


        Example:
        Device> enable
         

        Enables privileged EXEC mode.

        • Enter your password if prompted.
         
        Step 2configure terminal


        Example:
        Device# configure terminal
         

        Enters global configuration mode.

         
        Step 3Enters one of the following commands:
        • parameter-map type inspect-global
        • parameter-map type inspect global


        Example:
        Device(config)# parameter-map type inspect-global
        Device(config)# parameter-map type inspect global
         
        Configures a global parameter map for connecting thresholds and timeouts and enters parameter-map type inspect configuration mode.
        • Based on your release, the parameter-map type inspect-global and the parameter-map type inspect global commands are supported. You cannot configure both these commands together.
        • Skip Step 5 if you configure the parameter-map type inspect-global command.
        Note   

        If you configure the parameter-map type inspect-global command, per-box configurations are not supported because, by default, all per-box configurations apply to all firewall sessions.

         
        Step 4max-incomplete number aggressive-aging high {value low value | percent percent low percent percent}


        Example:
        Device(config-profile)# max-incomplete 3455 aggressive-aging high 2345 low 2255
         

        Configures the maximum limit and the aggressive aging limit of half-opened firewall sessions.

         
        Step 5session total number [aggressive-aging high {value low value | percent percent low percent percent}]


        Example:
        Device(config-profile)# session total 1000 aggressive-aging high percent 80 low percent 60
         

        Configures the total limit and the aggressive aging limit for total firewall sessions.

         
        Step 6exit


        Example:
        Device(config-profile)# exit
         

        Exits parameter-map type inspect configuration mode and enters global configuration mode.

         
        Step 7parameter-map type inspect parameter-map-name


        Example:
        Device(config)# parameter-map type inspect pmap1
         

        Configures an inspect-type parameter map for connecting thresholds, timeouts, and other parameters pertaining to the inspect action and enters parameter-map type inspect configuration mode.

         
        Step 8tcp synwait-time seconds [ageout-time seconds]


        Example:
        Device(config-profile)# tcp synwait-time 30 ageout-time 10
         

        Specifies how long the software will wait for a TCP session to reach the established state before dropping the session.

        • After aggressive aging is enabled, the SYN wait timer of the oldest TCP connections are reset from the default to the configured ageout time. In this example, instead of waiting for 30 seconds for connections to timeout, the timeout of the oldest TCP connections are set to 10 seconds. Aggressive aging is disabled when the connections drop below the low watermark.
         
        Step 9end


        Example:
        Device(config-profile)# end
         

        Exits parameter-map type inspect configuration mode and enters privileged EXEC mode.

         
        Step 10show policy-firewall stats vrf global


        Example:
        Device# show policy-firewall stats vrf global
         

        Displays global VRF firewall policy statistics.

         

        Configuring per-VRF Aggressive Aging

        SUMMARY STEPS

          1.    enable

          2.    configure terminal

          3.    ip vrf vrf-name

          4.    rd route-distinguisher

          5.    route-target export route-target-ext-community

          6.    route-target import route-target-ext-community

          7.    exit

          8.    parameter-map type inspect-vrf vrf-pmap-name

          9.    max-incomplete number aggressive-aging high {value low value | percent percent low percent percent}

          10.    session total number [aggressive-aging {high value low value | percent percent low percent percent}]

          11.    alert on

          12.    exit

          13.    Enter one of the following commands:

          • parameter-map type inspect-global
          • parameter-map type inspect global

          14.    vrf vrf-name inspect vrf-pmap-name

          15.    exit

          16.    parameter-map type inspect parameter-map-name

          17.    tcp idle-time seconds [ageout-time seconds]

          18.    tcp synwait-time seconds [ageout-time seconds]

          19.    exit

          20.    policy-map type inspect policy-map-name

          21.    class type inspect match-any class-map-name

          22.    inspect parameter-map-name

          23.    end

          24.    show policy-firewall stats vrf vrf-pmap-name


        DETAILED STEPS
           Command or ActionPurpose
          Step 1 enable


          Example:
          Device> enable
           

          Enables privileged EXEC mode.

          • Enter your password if prompted.
           
          Step 2configure terminal


          Example:
          Device# configure terminal
           

          Enters global configuration mode.

           
          Step 3ip vrf vrf-name


          Example:
          Device(config)# ip vrf ddos-vrf1
           

          Defines a VRF instance and enters VRF configuration mode.

           
          Step 4rd route-distinguisher


          Example:
          Device(config-vrf)# rd 100:2
           

          Specifies a route distinguisher (RD) for a VRF instance.

           
          Step 5route-target export route-target-ext-community


          Example:
          Device(config-vrf)# route-target export 100:2
           

          Creates a route-target extended community and exports the routing information to the target VPN extended community.

           
          Step 6route-target import route-target-ext-community


          Example:
          Device(config-vrf)# route-target import 100:2
           

          Creates a route-target extended community and imports routing information from the target VPN extended community.

           
          Step 7exit


          Example:
          Device(config-vrf)# exit
           

          Exits VRF configuration mode and enters global configuration mode.

           
          Step 8parameter-map type inspect-vrf vrf-pmap-name


          Example:
          Device(config)# parameter-map type inspect-vrf vrf1-pmap
           

          Configures an inspect VRF-type parameter map and enters parameter-map type inspect configuration mode.

           
          Step 9max-incomplete number aggressive-aging high {value low value | percent percent low percent percent}


          Example:
          Device(config-profile)# max-incomplete 2000 aggressive-aging high 1500 low 1200
           

          Configures the maximum limit and the aggressive aging limit for half-opened sessions.

           
          Step 10session total number [aggressive-aging {high value low value | percent percent low percent percent}]


          Example:
          Device(config-profile)# session total 1000 aggressive-aging high percent 80 low percent 60
           

          Configures the total session limit and the aggressive aging limit for the total sessions.

          • You can configure the total session limit as an absolute value or as a percentage.
           
          Step 11alert on


          Example:
          Device(config-profile)# alert on
           

          Enables the console display of stateful packet inspection alert messages.

           
          Step 12exit


          Example:
          Device(config-profile)# exit
           

          Exits parameter-map type inspect configuration mode and enters global configuration mode.

           
          Step 13Enter one of the following commands:
          • parameter-map type inspect-global
          • parameter-map type inspect global


          Example:
          Device(config)# parameter-map type inspect-global
          Device(config)# parameter-map type inspect global
           
          Configures a global parameter map and enters parameter-map type inspect configuration mode.
          • Based on your release, the parameter-map type inspect-global and the parameter-map type inspect global commands are supported. You cannot configure both these commands together.
          • Skip Step 14 if you configure the parameter-map type inspect-global command.
          Note   

          If you configure the parameter-map type inspect-global command, per-box configurations are not supported because, by default, all per-box configurations apply to all firewall sessions.

           
          Step 14vrf vrf-name inspect vrf-pmap-name


          Example:
          Device(config-profile)# vrf vrf1 inspect vrf1-pmap
           

          Binds a VRF with a parameter map.

           
          Step 15exit


          Example:
          Device(config-profile)# exit
           

          Exits parameter-map type inspect configuration mode and enters global configuration mode.

           
          Step 16parameter-map type inspect parameter-map-name


          Example:
          Device(config)# parameter-map type inspect pmap1
           

          Configures an inspect-type parameter map for connecting thresholds, timeouts, and other parameters pertaining to the inspect action and enters parameter-map type inspect configuration mode.

           
          Step 17tcp idle-time seconds [ageout-time seconds]


          Example:
          Device(config-profile)# tcp idle-time 3000 ageout-time 100
           

          Configures the timeout for idle TCP sessions and the aggressive aging-out time for TCP sessions.

           
          Step 18tcp synwait-time seconds [ageout-time seconds]


          Example:
          Device(config-profile)# tcp synwait-time 30 ageout-time 10
           

          Specifies how long the software will wait for a TCP session to reach the established state before dropping the session.

          • When aggressive aging is enabled, the SYN wait timer of the oldest TCP connections are reset from the default to the configured ageout time. In this example, instead of waiting for 30 seconds for connections to timeout, the timeout of the oldest TCP connections are set to 10 seconds. Aggressive aging is disabled when the connections drop below the low watermark.
           
          Step 19exit


          Example:
          Device(config-profile)# exit
           

          Exits parameter-map type inspect configuration mode and enters global configuration mode.

           
          Step 20policy-map type inspect policy-map-name


          Example:
          Device(config)# policy-map type inspect ddos-fw
           

          Creates a protocol-specific inspect type policy map and enters QoS policy-map configuration mode.

           
          Step 21class type inspect match-any class-map-name


          Example:
          Device(config-pmap)# class type inspect match-any ddos-class
           

          Specifies the traffic (class) on which an action is to be performed and enters QoS policy-map class configuration mode.

           
          Step 22inspect parameter-map-name


          Example:
          Device(config-pmap-c)# inspect pmap1
           

          Enables stateful packet inspection for the parameter map.

           
          Step 23end


          Example:
          Device(config-pmap-c)# end
           

          Exits QoS policy-map class configuration mode and enters privileged EXEC mode.

           
          Step 24show policy-firewall stats vrf vrf-pmap-name


          Example:
          Device# show policy-firewall stats vrf vrf1-pmap
           

          Displays VRF-level policy firewall statistics.

           
          Example

          The following is sample output from the show policy-firewall stats vrf vrf1-pmap command: 

          Device# show policy-firewall stats vrf vrf1-pmap

VRF: vrf1, Parameter-Map: vrf1-pmap
  Interface reference count: 2
       Total Session Count(estab + half-open): 80, Exceed: 0
       Total Session Aggressive Aging Period Off, Event Count: 0

                Half Open
       Protocol Session Cnt     Exceed
       -------- -----------     ------
       All      0               0
       UDP      0               0
       ICMP     0               0
       TCP      0               0

       TCP Syn Flood Half Open Count: 0, Exceed: 116
       Half Open Aggressive Aging Period Off, Event Count: 0

          Configuring the Aging Out of Firewall Sessions

          You can configure the aging out of ICMP, TCP, or UDP firewall sessions.

          SUMMARY STEPS

            1.    enable

            2.    configure terminal

            3.    Enter one of the following commands:

            • parameter-map type inspect-global
            • parameter-map type inspect global

            4.    vrf vrf-name inspect vrf-pmap-name

            5.    exit

            6.    parameter-map type inspect parameter-map-name

            7.    tcp idle-time seconds [ageout-time seconds]

            8.    tcp synwait-time seconds [ageout-time seconds]

            9.    exit

            10.    policy-map type inspect policy-map-name

            11.    class type inspect match-any class-map-name

            12.    inspect parameter-map-name

            13.    end

            14.    show policy-firewall stats vrf vrf-pmap-name


          DETAILED STEPS
             Command or ActionPurpose
            Step 1 enable


            Example:
            Device> enable
             

            Enables privileged EXEC mode.

            • Enter your password if prompted.
             
            Step 2configure terminal


            Example:
            Device# configure terminal
             

            Enters global configuration mode.

             
            Step 3Enter one of the following commands:
            • parameter-map type inspect-global
            • parameter-map type inspect global


            Example:
            Device(config)# parameter-map type inspect-global
            Device(config)# parameter-map type inspectglobal
             
            Configures a global parameter map and enters parameter-map type inspect configuration mode.
            • Based on your release, the parameter-map type inspect-global and the parameter-map type inspect global commands are supported. You cannot configure both these commands together.
            • Skip Step 4 if you configure the parameter-map type inspect-global command.
            Note   

            If you configure the parameter-map type inspect-global command, per-box configurations are not supported because, by default, all per-box configurations apply to all firewall sessions.

             
            Step 4vrf vrf-name inspect vrf-pmap-name


            Example:
            Device(config-profile)# vrf vrf1 inspect vrf1-pmap
             

            Binds a VRF with a parameter map.

             
            Step 5exit


            Example:
            Device(config-profile)# exit
             

            Exits parameter-map type inspect configuration mode and enters global configuration mode.

             
            Step 6parameter-map type inspect parameter-map-name


            Example:
            Device(config)# parameter-map type inspect pmap1
             

            Configures an inspect-type parameter map for connecting thresholds, timeouts, and other parameters pertaining to the inspect action and enters parameter-map type inspect configuration mode.

             
            Step 7tcp idle-time seconds [ageout-time seconds]


            Example:
            Device(config-profile)# tcp idle-time 3000 ageout-time 100
             
            Configures the timeout for idle TCP sessions and the aggressive aging-out time for TCP sessions.
            • You can also configure the tcp finwait-time command to specify how long a TCP session will be managed after the firewall detects a finish (FIN) exchange, or you can configure the tcp synwait-time command to specify how long the software will wait for a TCP session to reach the established state before dropping the session.
             
            Step 8tcp synwait-time seconds [ageout-time seconds]


            Example:
            Device(config-profile)# tcp synwait-time 30 ageout-time 10
             

            Specifies how long the software will wait for a TCP session to reach the established state before dropping the session.

            • When aggressive aging is enabled, the SYN wait timer of the oldest TCP connections are reset from the default to the configured ageout time. In this example, instead of waiting for 30 seconds for connections to timeout, the timeout of the oldest TCP connections are set to 10 seconds. Aggressive aging is enabled when the connections drop below the low watermark.
             
            Step 9exit


            Example:
            Device(config-profile)# exit
             

            Exits parameter-map type inspect configuration mode and enters global configuration mode.

             
            Step 10policy-map type inspect policy-map-name


            Example:
            Device(config)# policy-map type inspect ddos-fw
             

            Creates a protocol-specific inspect type policy map and enters QoS policy-map configuration mode.

             
            Step 11class type inspect match-any class-map-name


            Example:
            Device(config-pmap)# class type inspect match-any ddos-class
             

            Specifies the traffic class on which an action is to be performed and enters QoS policy-map class configuration mode.

             
            Step 12inspect parameter-map-name


            Example:
            Device(config-pmap-c)# inspect pmap1
             

            Enables stateful packet inspection for the parameter map.

             
            Step 13end


            Example:
            Device(config-pmap-c)# end
             

            Exits QoS policy-map class configuration mode and enters privileged EXEC mode.

             
            Step 14show policy-firewall stats vrf vrf-pmap-name


            Example:
            Device# show policy-firewall stats vrf vrf1-pmap
             

            Displays VRF-level policy firewall statistics.

             
            Example

            The following is sample output from the show policy-firewall stats vrf vrf1-pmap command: 

            Device# show policy-firewall stats vrf vrf1-pmap

 VRF: vrf1, Parameter-Map: vrf1-pmap
  Interface reference count: 2
       Total Session Count(estab + half-open): 270, Exceed: 0
       Total Session Aggressive Aging Period Off, Event Count: 0

                Half Open
       Protocol Session Cnt     Exceed
       -------- -----------     ------
       All      0               0
       UDP      0               0
       ICMP     0               0
       TCP      0               0

       TCP Syn Flood Half Open Count: 0, Exceed: 12       
       Half Open Aggressive Aging Period Off, Event Count: 0

            Configuring Firewall Event Rate Monitoring

            SUMMARY STEPS

              1.    enable

              2.    configure terminal

              3.    parameter-map type inspect-zone zone-pmap-name

              4.    alert on

              5.    threat-detection basic-threat

              6.    threat-detection rate fw-drop average-time-frame seconds average-threshold packets-per-second burst-threshold packets-per-second

              7.    threat-detection rate inspect-drop average-time-frame seconds average-threshold packets-per-second burst-threshold packets-per-second

              8.    threat-detection rate syn-attack average-time-frame seconds average-threshold packets-per-second burst-threshold packets-per-second

              9.    exit

              10.    zone security security-zone-name

              11.    protection parameter-map-name

              12.    exit

              13.    zone-pair security zone-pair-name source source-zone destination destination-zone

              14.    end

              15.    show policy-firewall stats zone


            DETAILED STEPS
               Command or ActionPurpose
              Step 1 enable


              Example:
              Device> enable
               

              Enables privileged EXEC mode.

              • Enter your password if prompted.
               
              Step 2configure terminal


              Example:
              Device# configure terminal
               

              Enters global configuration mode.

               
              Step 3parameter-map type inspect-zone zone-pmap-name


              Example:
              Device(config)# parameter-map type inspect-zone zone-pmap1
               

              Configures an inspect-zone parameter map and enters parameter-map type inspect configuration mode.

               
              Step 4alert on


              Example:
              Device(config-profile)# alert on
               
              Enables the console display of stateful packet inspection alert messages for a zone.
              • You can use the log command to configure the logging of alerts either to the syslog or to the high-speed logger (HSL).
               
              Step 5threat-detection basic-threat


              Example:
              Device(config-profile)# threat-detection basic-threat
               

              Configures basic threat detection for a zone.

               
              Step 6threat-detection rate fw-drop average-time-frame seconds average-threshold packets-per-second burst-threshold packets-per-second


              Example:
              Device(config-profile)# threat-detection rate fw-drop average-time-frame 600 average-threshold 100 burst-threshold 100
               
              Configures the threat detection rate for firewall drop events.
              • You must configure the threat-detection basic-threat command before you configure the threat-detection rate command.
               
              Step 7threat-detection rate inspect-drop average-time-frame seconds average-threshold packets-per-second burst-threshold packets-per-second


              Example:
              Device(config-profile)# threat-detection rate inspect-drop average-time-frame 600 average-threshold 100 burst-threshold 100
               

              Configures the threat detection rate for firewall inspection-based drop events.

               
              Step 8threat-detection rate syn-attack average-time-frame seconds average-threshold packets-per-second burst-threshold packets-per-second


              Example:
              Device(config-profile)# threat-detection rate syn-attack average-time-frame 600 average-threshold 100 burst-threshold 100
               

              Configures the threat detection rate for TCP SYN attack events.

               
              Step 9exit


              Example:
              Device(config-profile)# exit
               

              Exits parameter-map type inspect configuration mode and enters global configuration mode.

               
              Step 10zone security security-zone-name


              Example:
              Device(config)# zone security public
               

              Creates a security zone and enters security zone configuration mode.

               
              Step 11protection parameter-map-name


              Example:
              Device(config-sec-zone)# protection zone-pmap1
               

              Attaches the inspect-zone parameter map to the zone and applies the features configured in the inspect-zone parameter map to the zone.

               
              Step 12exit


              Example:
              Device(config-sec-zone)# exit
               

              Exits security zone configuration mode and enters global configuration mode.

               
              Step 13zone-pair security zone-pair-name source source-zone destination destination-zone


              Example:
              Device(config)# zone-pair security private2public source private destination public
               

              Creates a zone pair and enters security zone-pair configuration mode.

               
              Step 14end


              Example:
              Device(config-sec-zone-pair)# end
               

              Exits security zone-pair configuration mode and enters privileged EXEC mode.

               
              Step 15show policy-firewall stats zone


              Example:
              Device# show policy-firewall stats zone
               

              Displays policy firewall statistics at the zone level.

               

              Configuring the per-Box Half-Opened Session Limit

              Per-box refers to the entire firewall session table. Any configuration that follows the parameter-map type inspect-global command applies to the box.

              SUMMARY STEPS

                1.    enable

                2.    configure terminal

                3.    Enter one of the following commands:

                • parameter-map type inspect-global
                • parameter-map type inspect global

                4.    alert on

                5.    per-box max-incomplete number

                6.    session total number

                7.    end

                8.    show policy-firewall stats global


              DETAILED STEPS
                 Command or ActionPurpose
                Step 1 enable


                Example:
                Device> enable
                 

                Enables privileged EXEC mode.

                • Enter your password if prompted.
                 
                Step 2configure terminal


                Example:
                Device# configure terminal
                 

                Enters global configuration mode.

                 
                Step 3Enter one of the following commands:
                • parameter-map type inspect-global
                • parameter-map type inspect global


                Example:
                Device(config)# parameter-map type inspect-global
                Device(config)# parameter-map type inspect global
                 

                Configures a global parameter map for connecting thresholds and timeouts and enters parameter-map type inspect configuration mode.

                • Based on your release, the parameter-map type inspect-global and the parameter-map type inspect global commands are supported. You cannot configure both these commands together.
                • Skip to Steps 5 and 6 if you configure the parameter-map type inspect-global command.
                Note   

                If you configure the parameter-map type inspect-global command, per-box configurations are not supported because, by default, all per-box configurations apply to all firewall sessions.

                 
                Step 4alert on


                Example:
                Device(config-profile)# alert on
                 

                Enables the console display of stateful packet inspection alert messages.

                 
                Step 5per-box max-incomplete number


                Example:
                Device(config-profile)# per-box max-incomplete 12345
                 

                Configures the maximum number of half-opened connections for the firewall session table.

                 
                Step 6session total number


                Example:
                Device(config-profile)# session total 34500
                 

                Configures the total session limit for the firewall session table.

                 
                Step 7end


                Example:
                Device(config-profile)# end
                 

                Exits parameter-map type inspect configuration mode and enters privileged EXEC mode.

                 
                Step 8show policy-firewall stats global


                Example:
                Device# show policy-firewall stats global
                 

                Displays global firewall statistics information.

                 

                Configuring the Half-Opened Session Limit for an Inspect-VRF Parameter Map

                SUMMARY STEPS

                  1.    enable

                  2.    configure terminal

                  3.    parameter-map type inspect-vrf vrf-name

                  4.    alert on

                  5.    max-incomplete number

                  6.    session total number

                  7.    exit

                  8.    Enter one of the following commands:

                  • parameter-map type inspect-global
                  • parameter-map type inspect global

                  9.    alert on

                  10.    vrf vrf-name inspect vrf-pmap-name

                  11.    end

                  12.    show policy-firewall stats vrf vrf-pmap-name


                DETAILED STEPS
                   Command or ActionPurpose
                  Step 1 enable


                  Example:
                  Device> enable
                   

                  Enables privileged EXEC mode.

                  • Enter your password if prompted.
                   
                  Step 2configure terminal


                  Example:
                  Device# configure terminal
                   

                  Enters global configuration mode.

                   
                  Step 3parameter-map type inspect-vrf vrf-name


                  Example:
                  Device(config)# parameter-map type inspect-vrf vrf1-pmap
                   

                  Configures an inspect-VRF parameter map and enters parameter-map type inspect configuration mode.

                   
                  Step 4alert on


                  Example:
                  Device(config-profile)# alert on
                   

                  Enables the console display of stateful packet inspection alert messages.

                   
                  Step 5max-incomplete number


                  Example:
                  Device(config-profile)# max-incomplete 2000
                   

                  Configures the maximum number of half-opened connections per VRF.

                   
                  Step 6session total number


                  Example:
                  Device(config-profile)# session total 34500
                   

                  Configures the total session limit for a VRF.

                   
                  Step 7exit


                  Example:
                  Device(config-profile)# exit
                   

                  Exits parameter-map type inspect configuration mode and enters global configuration mode.

                   
                  Step 8Enter one of the following commands:
                  • parameter-map type inspect-global
                  • parameter-map type inspect global


                  Example:
                  Device(config)# parameter-map type inspect-global
                  Device(config)# parameter-map type inspect global
                   
                  Configures a global parameter map for connecting thresholds and timeouts and enters parameter-map type inspect configuration mode.
                  • Based on your release, you can use either the parameter-map type inspect-global command or the parameter-map type inspect global command. You cannot configure both these commands together.
                  • Skip Step 10 if you configure the parameter-map type inspect-global command.
                  Note   

                  If you configure the parameter-map type inspect-global command, per-box configurations are not supported because, by default, all per-box configurations apply to all firewall sessions.

                   
                  Step 9alert on


                  Example:
                  Device(config-profile)# alert on
                   

                  Enables the console display of stateful packet inspection alert messages.

                   
                  Step 10vrf vrf-name inspect vrf-pmap-name


                  Example:
                  Device(config-profile)# vrf vrf1 inspect vrf1-pmap
                   

                  Binds the VRF to the global parameter map.

                   
                  Step 11end


                  Example:
                  Device(config-profile)# end
                   

                  Exits parameter-map type inspect configuration mode and enters privileged EXEC mode.

                   
                  Step 12show policy-firewall stats vrf vrf-pmap-name


                  Example:
                  Device# show policy-firewall stats vrf vrf1-pmap
                   

                  Displays VRF-level policy firewall statistics.

                   

                  Configuring the Global TCP SYN Flood Limit

                  SUMMARY STEPS

                    1.    enable

                    2.    configure terminal

                    3.    Enter one of the following commands:

                    • parameter-map type inspect-global
                    • parameter-map type inspect global

                    4.    alert on

                    5.    per-box tcp syn-flood limit number

                    6.    end

                    7.    show policy-firewall stats vrf global


                  DETAILED STEPS
                     Command or ActionPurpose
                    Step 1 enable


                    Example:
                    Device> enable
                     

                    Enables privileged EXEC mode.

                    • Enter your password if prompted.
                     
                    Step 2 configure terminal


                    Example:
                    Device# configure terminal
                     

                    Enters global configuration mode.

                     
                    Step 3Enter one of the following commands:
                    • parameter-map type inspect-global
                    • parameter-map type inspect global


                    Example:
                    Device(config)# parameter-map type inspect-global
                    Device(config)# parameter-map type inspect global
                     

                    Configures a global parameter map and enters parameter-map type inspect configuration mode.

                    • Based on your release, you can configure either the parameter-map type inspect-global command or the parameter-map type inspect global command. You cannot configure both these commands together.
                    • Skip Step 5 if you configure the parameter-map type inspect-global command.
                    Note   

                    If you configure the parameter-map type inspect-global command, per-box configurations are not supported because, by default, all per-box configurations apply to all firewall sessions.

                     
                    Step 4 alert on


                    Example:
                    Device(config-profile)# alert on
                     

                    Enables the console display of stateful packet inspection alert messages.

                     
                    Step 5 per-box tcp syn-flood limit number


                    Example:
                    Device(config-profile)# per-box tcp syn-flood limit 500
                     

                    Limits the number of TCP half-opened sessions that trigger SYN cookie processing for new SYN packets.

                     
                    Step 6 end


                    Example:
                    Device(config-profile)# end
                     

                    Exits parameter-map type inspect configuration mode and enters privileged EXEC mode.

                     
                    Step 7 show policy-firewall stats vrf global


                    Example:
                    Device# show policy-firewall stats vrf global
                     

                    (Optional) Displays the status of the global VRF firewall policy.

                    • The command output also displays how many TCP half-opened sessions are present.
                     

                    Example

                    The following is sample output from the show policy-firewall stats vrf global command: 

                    Device# show policy-firewall stats vrf global
 
Global table statistics
       total_session_cnt: 0
       exceed_cnt:        0
       tcp_half_open_cnt: 0
       syn_exceed_cnt:    0

                    Configuring Firewall Resource Management


                    Note

                    A global parameter map takes effect on the global routing domain and not at the router level.

                    SUMMARY STEPS

                      1.    enable

                      2.    configure terminal

                      3.    parameter-map type inspect-vrf vrf-pmap-name

                      4.    session total number

                      5.    tcp syn-flood limit number

                      6.    exit

                      7.    parameter-map type inspect-global

                      8.    vrf vrf-name inspect parameter-map-name

                      9.    exit

                      10.    parameter-map type inspect-vrf vrf-default

                      11.    session total number

                      12.    tcp syn-flood limit number

                      13.    end


                    DETAILED STEPS
                       Command or ActionPurpose
                      Step 1 enable


                      Example:
                      Device> enable
                       

                      Enables privileged EXEC mode.

                      • Enter your password if prompted.
                       
                      Step 2 configure terminal


                      Example:
                      Device# configure terminal
                       

                      Enters global configuration mode.

                       
                      Step 3 parameter-map type inspect-vrf vrf-pmap-name


                      Example:
                      Device(config)# parameter-map type inspect-vrf vrf1-pmap
                       

                      Configures an inspect VRF-type parameter map and enters parameter-map type inspect configuration mode.

                       
                      Step 4 session total number


                      Example:
                      Device(config-profile)# session total 1000
                       

                      Configures the total number of sessions.

                       
                      Step 5 tcp syn-flood limit number


                      Example:
                      Device(config-profile)# tcp syn-flood limit 2000
                       

                      Limits the number of TCP half-opened sessions that trigger synchronization (SYN) cookie processing for new SYN packets.

                       
                      Step 6 exit


                      Example:
                      Device(config-profile)# exit
                       

                      Exits parameter-map type inspect configuration mode and enters global configuration mode.

                       
                      Step 7 parameter-map type inspect-global


                      Example:
                      Device(config)# parameter-map type inspect-global
                       

                      Configures a global parameter map and enters parameter-map type inspect configuration mode.

                       
                      Step 8 vrf vrf-name inspect parameter-map-name


                      Example:
                      Device(config-profile)# vrf vrf1 inspect vrf1-pmap
                       

                      Binds a VRF to the parameter map.

                       
                      Step 9 exit


                      Example:
                      Device(config-profile)# exit
                       

                      Exits parameter-map type inspect configuration mode and enters global configuration mode.

                       
                      Step 10 parameter-map type inspect-vrf vrf-default


                      Example:
                      Device(config)# parameter-map type inspect-vrf vrf-default
                       

                      Configures a default inspect VRF-type parameter map.

                       
                      Step 11 session total number


                      Example:
                      Device(config-profile)# session total 6000
                       

                      Configures the total number of sessions.

                      • You can configure the session total command for an inspect VRF-type parameter map and for a global parameter map. When you configure the session total command for an inspect VRF-type parameter map, the sessions are associated with an inspect VRF-type parameter map. The session total command is applied to the global routing domain when it is configured for a global parameter-map.
                       
                      Step 12 tcp syn-flood limit number


                      Example:
                      Device(config-profile)# tcp syn-flood limit 7000
                       

                      Limits the number of TCP half-opened sessions that trigger SYN cookie processing for new SYN packets.

                       
                      Step 13 end


                      Example:
                      Device(config-profile)# end
                       

                      Exits parameter-map type inspect configuration mode and enters privileged EXEC mode.

                       

                      Configuration Examples for IPv6 Firewall Support for Prevention of Distributed Denial of Service Attacks and Resource Management

                      Example: Configuring an IPv6 Firewall

                      Device# configure terminal
Device(config)# vrf-definition VRF1
Device(config-vrf)# address-family ipv6
Device(config-vrf-af)# exit-address-family
Device(config-vrf)# exit
Device(config)# parameter-map type inspect ipv6-param-map
Device(config-profile)# sessions maximum 10000
Device(config-profile)# exit
Device(config)# ipv6 unicast-routing
Device(config)# ip port-map ftp port 8090 list ipv6-acl
Device(config)# ipv6 access-list ipv6-acl
Device(config-ipv6-acl)# permit ipv6 any any
Device(config-ipv6-acl)# exit
Device(config)# class-map type inspect match-all ipv6-class
Device(config-cmap)# match access-group name ipv6-acl
Device(config-cmap)# match protocol tcp
Device(config-cmap)# exit
Device(config)# policy-map type inspect ipv6-policy
Device(config-pmap)# class type inspect ipv6-class
Device(config-pmap-c)# inspect ipv6-param-map
Device(config-pmap-c)# end

                      Example: Configuring the Aggressive Aging of Firewall Sessions

                      Example: Configuring per-Box Aggressive Aging

                      Device# configure terminal
Device(config)# parameter-map type inspect global
Device(config-profile)# per-box max-incomplete 2000 aggressive-aging 1500 low 1200
Device(config-profile)# per-box aggressive-aging high 1700 low 1300
Device(config-profile)# exit
Device(config)# parameter-map type inspect pmap1
Device(config-profile)# tcp synwait-time 30 ageout-time 10
Device(config-profile)# end

                      Example: Configuring Aggressive Aging for a Default VRF

                      Device# configure terminal
Device(config)# parameter-map type inspect global
Device(config-profile)# max-incomplete 2000 aggressive-aging high 1500 low 1200
Device(config-profile)# session total 1000 aggressive-aging high percent 80 low percent 60
Device(config-profile)# exit
Device(config)# parameter-map type inspect pmap1
Device(config-profile)# tcp synwait-time 30 ageout-time 10
Device(config-profile)# end

                      Example: Configuring per-VRF Aggressive Aging

                      Device# configure terminal
Device(config)# ip vrf ddos-vrf1
Device(config-vrf)# rd 100:2
Device(config-vrf)# route-target export 100:2
Device(config-vrf)# route-target import 100:2
Device(config-vrf)# exit
Device(config)# parameter-map type inspect-vrf vrf1-pmap
Device(config-profile)# max-incomplete 3455 aggressive-aging high 2345 low 2255
Device(config-profile)# session total 1000 aggressive-aging high percent 80 low percent 60
Device(config-profile)# alert on
Device(config-profile)# exit
Device(config)# parameter-map type inspect global
Device(config-profile)# vrf vrf1 inspect vrf1-pmap
Device(config-profile)# exit
Device(config)# parameter-map type inspect pmap1
Device(config-profile)# tcp idle-time 3000 ageout-time 100
Device(config-profile)# tcp synwait-time 30 ageout-time 10
Device(config-profile)# exit
Device(config)# policy-map type inspect ddos-fw
Device(config-pmap)# class type inspect match-any ddos-class
Device(config-pmap-c)# inspect pmap1
Device(config-profile)# end

                      Example: Configuring the Aging Out of Firewall Sessions

                      Device# configure terminal
Device(config-profile)# exit
Device(config)# parameter-map type inspect global
Device(config-profile)# vrf vrf1 inspect vrf1-pmap
Device(config-profile)# exit
Device(config)# parameter-map type inspect pmap1
Device(config-profile)# tcp idle-time 3000 ageout-time 100
Device(config-profile)# tcp synwait-time 30 ageout-time 10
Device(config-profile)# exit
Device(config)# policy-map type inspect ddos-fw
Device(config-profile)# class type inspect match-any ddos-class
Device(config-profile)# inspect pmap1
Device(config-profile)# end

                      Example: Configuring Firewall Event Rate Monitoring

                      Device> enable
Device# configure terminal
Device(config)# parameter-map type inspect zone zone-pmap1
Device(config-profile)# alert on
Device(config-profile)# threat-detection basic-threat
Device(config-profile)# threat-detection rate fw-drop average-time-frame 600 average-threshold 100 burst-threshold 100
Device(config-profile)# threat-detection rate inspect-drop average-time-frame 600 average-threshold 100 burst-threshold 100
Device(config-profile)# threat-detection rate syn-attack average-time-frame 600 average-threshold 100 burst-threshold 100
Device(config-profile)# exit
Device(config)# zone security public
Device(config-sec-zone)# protection zone-pmap1
Device(config-sec-zone)# exit
Device(config)# zone-pair security private2public source private destination public
Device(config-sec-zone-pair)# end

                      Example: Configuring the per-Box Half-Opened Session Limit

                      Device# configure terminal  
Device(config)# parameter-map type inspect global 
Device(config-profile)# alert on 
Device(config-profile)# per-box max-incomplete 12345   
Device(config-profile)# session total 34500  
Device(config-profile)# end

                      Example: Configuring the Half-Opened Session Limit for an Inspect VRF Parameter Map

                      Device# configure terminal  
Device(config)# parameter-map type inspect vrf vrf1-pmap 
Device(config-profile)# alert on 
Device(config-profile)# max-incomplete 3500 
Device(config-profile)# session total 34500 
Device(config-profile)# exit
Device(config)# parameter-map type inspect global
Device(config-profile)# alert on
Device(config-profile)# vrf vrf1 inspect vrf1-pmap 
Device(config-profile)# end

                      Example: Configuring the Global TCP SYN Flood Limit

                      Device# configure terminal  
Device(config)# parameter-map type inspect global 
Device(config-profile)# alert on 
Device(config-profile)# per-box tcp syn-flood limit 500 
Device(config-profile)# end

                      Example: Configuring Firewall Resource Management

                      Device# configure terminal
Device(config)# parameter-map type inspect-vrf vrf1-pmap
Device(config-profile)# session total 1000
Device(config-profile)# tcp syn-flood limit 2000
Device(config-profile)# exit
Device(config)# parameter-map type inspect-global
Device(config-profile)# vrf vrf1 inspect pmap1
Device(config-profile)# exit
Device(config)# parameter-map type inspect-vrf vrf-default
Device(config-profile)# session total 6000
Device(config-profile)# tcp syn-flood limit 7000
Device(config-profile)# end

                      Additional References for IPv6 Firewall Support for Prevention of Distributed Denial of Service Attacks and Resource Management

                      Related Documents

                      Related Topic

                      Document Title

                      Cisco IOS commands

                      Cisco IOS Master Command List, All Releases

                      Security commands

                      Technical Assistance

                      Description

                      Link

                      The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

                      http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

                      Feature Information for IPv6 Firewall Support for Prevention of Distributed Denial of Service Attacks and Resource Management

                      The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

                      Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

                      Table 2 Feature Information for IPv6 Firewall Support for Prevention of Distributed Denial of Service Attacks and Resource Management

                      Feature Name

                      Releases

                      Feature Information

                      IPv6 Firewall Support for Prevention of Distributed Denial of Service Attacks and Resource Management

                      Cisco IOS XE Release 3.7S

                      IPv6 zone-based firewalls support the Protection of Distributed Denial of Service Attacks and the Firewall Resource Management features.

                      The Protection Against Distributed Denial of Service Attacks feature provides protection from Denial of Service (DoS) attacks at the global level (for all firewall sessions) and at the VPN routing and forwarding (VRF) level. You can configure the aggressive aging of firewall sessions, event rate monitoring of firewall sessions, half-opened connections limit, and global TCP SYN cookie protection to prevent distributed DoS attacks.

                      The Firewall Resource Management feature limits the number of VPN routing and forwarding (VRF) instances and global firewall sessions that are configured on a device.