- Preface
- New and Changed Information
- Overview
- Managing User Accounts
- Configuring VSD
- Configuring AAA
- Configuring RADIUS
- Configuring TACACS+
- Configuring SSH
- Configuring Telnet
- Configuring IP ACLs
- Configuring MAC ACLs
- Configuring Port Security
- Configuring DHCP Snooping
- Configuring Dynamic ARP Inspection
- Configuring IP Source Guard
- Disabling the HTTP Server
- Blocking Unknown Unicast Flooding
- Configuring Cisco TrustSec
- Index
Cisco Nexus 1000V Security Configuration Guide, 4.2(1)SV2(1.1)
Bias-Free Language
The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.
- Updated:
- March 3, 2015
Chapter: Configuring IP ACLs
Configuring IP ACLs
This chapter contains the following sections:
- Information About ACLs
- Prerequisites for IP ACLs
- Guidelines and Limitations for IP ACLs
- Default Settings for IP ACLs
- Configuring IP ACLs
- Verifying the IP ACL Configuration
- Monitoring IP ACLs
- Configuration Example for IP ACL
- Feature History for IP ACLs
Information About ACLs
An ACL is an ordered set of rules that you can use to filter traffic. Each rule specifies a set of conditions that a packet must satisfy to match the rule. When the device determines that an ACL applies to a packet, it tests the packet against the conditions of all rules. The rule determines whether the packet is to be permitted or denied. If there is no match to any of the specified rules, the device applies the applicable implicit rule. The device continues processing packets that are permitted and drops packets that are denied.
You can use ACLs to protect networks and specific hosts from unnecessary or unwanted traffic. For example, you can use ACLs to disallow HTTP traffic from a high-security network to the Internet. You can also use ACLs to allow HTTP traffic to a specific site using the IP address of the site to identify it in an IP ACL.
ACL Types and Applications
An ACL is considered a port ACL when you apply it to one of the following:
When a port ACL is applied to a trunk port, the ACL filters traffic on all VLANs on that trunk port.
The following types of port ACLs are supported for traffic filtering:
Order of ACL Application
When the device processes a packet, it determines the forwarding path of the packet. The device applies the ACLs in the following order:
Rules
Rules are what you create, modify, and remove when you configure how an ACL filters network traffic. Rules appear in the running configuration. When you apply an ACL to an interface or change a rule within an ACL that is already applied to an interface, the supervisor module creates ACL entries from the rules in the running configuration and sends those ACL entries to the applicable VEM.
You can create rules in ACLs in access-list configuration mode by using the permit or deny command. The device allows traffic that matches the criteria in a permit rule and blocks traffic that matches the criteria in a deny rule. You have many options for configuring the criteria that traffic must meet in order to match the rule.
Source and Destination
In each rule, you specify the source and the destination of the traffic that matches the rule. You can specify both the source and destination as a specific host, a network or group of hosts, or any host. How you specify the source and destination depends on whether you are configuring IP or MAC ACLs. For information about specifying the source and destination, see the applicable permit and deny commands in the Cisco Nexus 1000V Command reference .
Protocols
IP and MAC ACLs allow you to identify traffic by protocol. You can specify some protocols by name. For example, in an IP ACL, you can specify ICMP by name.
You can specify any protocol by number. In MAC ACLs, you can specify protocols by the EtherType number of the protocol, which is a hexadecimal number. For example, you can use 0x0800 to specify IP traffic in a MAC ACL rule.
In IP ACLs, you can specify protocols by the integer that represents the Internet protocol number. For example, you can use 115 to specify Layer 2 Tunneling Protocol (L2TP) traffic. For a list of the protocols that each type of ACL supports by name, see the applicable permit and deny commands in the Cisco Nexus 1000V Command Reference .
Implicit Rules
IP and MAC ACLs have implicit rules, which means that although these rules do not appear in the running configuration, the device applies them to traffic when no other rules in an ACL match. When you configure the device to maintain per-rule statistics for an ACL, the device does not maintain statistics for implicit rules.
All IP ACLs include the following implicit rule that denies unmatched IP traffic:
deny ip any any
All MAC ACLs include the following implicit rule:
deny any any
This implicit rule ensures that unmatched traffic is denied, regardless of the protocol specified in the Layer 2 header of the traffic.
Additional Filtering Options
You can identify traffic by using additional options. These options differ by ACL type. The following list includes most but not all additional filtering options:
IP ACLs support the following additional filtering options:
MAC ACLs support the following additional filtering options:
See the Cisco Nexus 1000V Command Reference guide for information about filtering options available when using the applicable permit and deny commands.
Sequence Numbers
The device supports sequence numbers for rules. Every rule that you enter receives a sequence number, either assigned by you or assigned automatically by the device. Sequence numbers simplify the following ACL tasks:
Adding new rules between existing rules—By specifying the sequence number, you specify where in the ACL a new rule should be positioned. For example, if you need to insert a rule between rules numbered 100 and 110, you could assign a sequence number of 105 to the new rule.
Removing a rule—Without using a sequence number, removing a rule requires that you enter the whole rule, as follows:
switch(config-acl)# no permit tcp 10.0.0.0/8 any
However, if the same rule had a sequence number of 101, removing the rule requires only the following command:
switch(config-acl)# no 101
Moving a rule—With sequence numbers, if you need to move a rule to a different position within an ACL, you can add a second instance of the rule by using the sequence number that positions it correctly, and then you can remove the original instance of the rule. This action allows you to move the rule without disrupting traffic.
If you enter a rule without a sequence number, the device adds the rule to the end of the ACL and assigns a sequence number that is 10 greater than the sequence number of the preceding rule to the rule. For example, if the last rule in an ACL has a sequence number of 225 and you add a rule without a sequence number, the device assigns the sequence number 235 to the new rule.
In addition, you can reassign sequence numbers to rules in an ACL. Resequencing is useful when an ACL has rules numbered contiguously, such as 100 and 101, and you need to insert one or more rules between those rules.
Statistics
The device can maintain global statistics for each rule that you configure in IPv4 and MAC ACLs. If an ACL is applied to multiple interfaces, the maintained rule statistics are the sum of packet matches (hits) on all the interfaces on which that ACL is applied.
 Note | The device does not support interface-level ACL statistics. |
For each ACL that you configure, you can specify whether the device maintains statistics for that ACL, which allows you to turn ACL statistics on or off as needed to monitor traffic filtered by an ACL or to help troubleshoot the configuration of an ACL.
The device does not maintain statistics for implicit rules in an ACL. For example, the device does not maintain a count of packets that match the implicit deny ip any any rule at the end of all IPv4 ACLs. If you want to maintain statistics for implicit rules, you must explicitly configure the ACL with rules that are identical to the implicit rules.
ACL Logging
You can use ACL logging to monitor flows that affect specific ACLs. The ACLs can be configured with the optional log keyword in each of the access control entries (ACEs). When you configure an option, statistics for each flow that match the ACL permit or deny conditions that you enter are logged in the software.
You can apply the log option to any ACL by entering the following commands:
switch(config)# ip access-list [name] switch(config-acl)# permit tcp any 156.10.3.44/24 log
An implicit deny rule is the default action for ACLs. To log any packets that match the implicit deny rule, you must create an explicit deny rule and add the log keyword.
ACL logging is applicable only to ACLs that are configured with the ip access-list command. Other traffic, such as the Virtual Supervisor Module (VSM) management interface or the selectors (aaa authen match, qos match, and so on), are not logged.
Statistics and logging are provided for each flow. A flow is defined by the following IP flows:
VSM ID
Virtual Ethernet Module (VEM) ID
Source interface
Protocol
Source IP address
Source port
Destination IP address
Destination port
Scalability is provided through the following functionality:
Each Cisco Nexus 1000V switch can support up to 64 VEMs.
Each VEM can support up to 5000 permits and 5000 denies flows. The maximum number of permit/deny flows is a configurable option.
The flow reporting interval can be set from 5 up to 86,400 seconds (1 day).
The configuration flow syslog level can be from 0 to 7.
Up to three syslog servers are supported.
ACL Flows
An ACL flow as it pertains to ACL logging has the following characteristics:
It represents a stream of IPv4 packets with the same packet headers (SrcIP, DstIP, Protocol, SrcPort, DstPort) for which an identical ACL action is enforced. Each flow entry tracks the count of packets that match the flow.
It is created only if logging is enabled on the corresponding ingress/egress ACL policy. Ingress and egress flows are tracked separately.
Each VEM tracks a maximum of 10,000 ACL flows; a flow space is shared between permit/deny flows, and each has a configurable maximum of 5000.
Each flow entry contains the following:
The ACL flow life cycle is as follows:
A flow is created when the first packet of a unidirectional stream matches a Layer 3 ACL policy. A new flow notification is sent to the syslog server.
For all subsequent packets with a tuple that matches the flow tuple, the per flow packet counter is incremented.
Each flow is tracked periodically based on the configured reporting interval. Within each periodic report, all the active flows and the corresponding packet count seen since the last periodic report are reported to the syslog server
If no packets match a flow for one full periodic interval, the flow entry is purged. This process is the only flow-aging scheme.
A flow is not stateful. There is no connection tracking for TCP flows.
The flow reporting process occurs in the following manner:
For each flow created, a new flow notification message is sent to the syslog server.
A periodic report for each active flow comes next. A flow is active if packets that match the flow are seen since the last periodic report.
The flow information is exported to the syslog server and contains the following: packet tuple, ACL action, direction, VEM-ID, VSM-ID, packet count.
The periodic time can be as low as 5 seconds with the default setting of 5 minutes. A new user space ACL-logging thread handles the periodic poll and report functionality.
Syslog messages that identify the flow space usage are sent at 75 percent, 90 percent, and 100 percent of the threshold maximum to the syslog server once during each interval.
Syslog Messages
Syslog message characteristics are as follows:
-
Syslog messages that contain flow information are exported from each Virtual Ethernet Module (VEM).
-
The syslog client functionality is RFC-5424 compliant and communicates to servers over a UDP port (514).
-
Any host that contains a VEM must be configured with a vmknic interface that can reach the remote syslog server.
-
On an ESXi-5.0 host, syslog messages are blocked by a firewall. The Cisco Nexus 1000V has installation scripts that open the firewall for port 514.
Prerequisites for IP ACLs
Guidelines and Limitations for IP ACLs
ACLs are not supported in port channels.
Default Settings for IP ACLs
Parameters |
Default |
|---|---|
IP ACLs |
No IP ACLs exist by default. |
ACL rules |
Implicit rules apply to all ACLs. |
Configuring IP ACLs
Creating an IP ACL
You can create an IPv4 ACL on the device and add rules to it.
Log in to the CLI in EXEC mode.
This example shows how to create an IP ACL:
switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
switch(config)# ip access-list acl-01
switch(config-acl)# permit ip 192.168.2.0/24 any
switch(config-acl)# statistics per-entry
switch(config-acl)# show ip access-lists acl-01
IPV4 ACL acl-01
statistics per-entry
10 permit ip 192.168.2.0/24 any
switch(config-acl)# copy running-config startup-config
Changing an IP ACL
You can add and remove rules in an existing IPv4 ACL. You cannot change existing rules. Instead, to change a rule, you can remove it and create it again with the desired changes.
If you need to add more rules between existing rules than the current sequence numbering allows, you can use the resequence command to reassign sequence numbers.
Log in to the CLI in EXEC mode.
This example shows how to change an IP ACL:
switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
switch(config)# ip access-list acl-01
switch(config-acl)# permit ip 192.168.2.0/24 any
switch(config-acl)# statistics per-entry
switch(config-acl)# show ip access-lists acl-01
IPV4 ACL acl-01
statistics per-entry
10 permit ip 192.168.2.0/24 any
switch(config-acl)# ip access-list acl-01
switch(config-acl)# no 10
switch(config-acl)# no statistics per-entry
switch(config-acl)# show ip access-lists acl-01
IPV4 ACL acl-01
switch(config-acl)# copy running-config startup-config
Removing an IP ACL
Before you remove an IP ACL from the switch, ensure that you know whether the ACL is applied to an interface. The switch allows you to remove ACLs that are currently applied. Removing an ACL does not affect the configuration of interfaces where you have applied the ACL. Instead, the switch considers the removed ACL to be empty, that is, empty ACL with implicit rule of deny IP any .Use the show ip access-lists command with the summary keyword to find the interfaces that an IP ACL is configured on.
This example shows how to remove an IP ACL:
switch# configure terminal switch(config)# no ip access-list acl-01 switch(config)# show ip access-lists acl-01 summary switch(config)# copy running-config startup-config
Changing Sequence Numbers in an IP ACL
You can change all the sequence numbers assigned to the rules in an IP ACL.
Log in to the CLI in EXEC mode.
This example shows how to change sequence numbers in an IP ACL:
switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
switch(config)# show ip access-lists acl-01
IPV4 ACL acl-01
statistics per-entry
10 permit ip 192.168.2.0/24 any
20 permit ip 192.168.5.0/24 any
switch(config)# resequence ip access-list acl-01 100 10
switch(config)# show ip access-lists acl-01
IPV4 ACL acl-01
statistics per-entry
100 permit ip 192.168.2.0/24 any
110 permit ip 192.168.5.0/24 any
switch(config)# copy running-config startup-config
Applying an IP ACL as a Port ACL
You can apply an IPv4 ACL to a physical Ethernet interface or a virtual Ethernet interface. ACLs applied to these interface types are considered port ACLs.
An IP ACL can also be applied on a port profile that is attached to a physical Ethernet interface or a virtual Ethernet interface.
Note | ACLs cannot be applied on a port-channel interface. However, an ACL can be applied on a physical Ethernet interface that is not part of the port channel. |
This example shows how to apply an IP ACL as a port ACL:
switch# configure terminal Enter configuration commands, one per line. End with CNTL/Z. switch(config)# interface vethernet 1 switch(config-if)# ip port access-group acl-01 in switch(config-if)# show running-config aclmgr ip access-list acl-01 statistics per-entry 100 permit ip 192.168.2.0/24 any 110 permit ip 192.168.5.0/24 any interface Vethernet1 ip port access-group acl-01 in switch(config-if)# copy running-config startup-config
Adding an IP ACL to a Port Profile
You can add an IP ACL to a port profile.
You must know the following information:
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | switch# configure terminal |
Enters global configuration mode. |
| Step 2 | switch(config)# port-profile [type {ethernet | vethernet}] name | Enters port profile configuration mode for the named port profile. |
| Step 3 | switch(config-port-prof)# ip port access-group name { in | out } | Adds the named ACL to the port profile for either inbound or outbound traffic. |
| Step 4 | switch(config-port-prof)# show port-profile [brief | expand-interface | usage] [name profile-name] | (Optional) Displays the configuration for verification. |
| Step 5 | switch(config-port-prof)# copy running-config startup-config | (Optional) Copies the running configuration to the startup configuration. |
This example shows how to add an IP ACL to a port profile:
switch# configure terminal Enter configuration commands, one per line. End with CNTL/Z. switch(config)# port-profile type vethernet vm_eth1 switch(config-port-prof)# ip port access-group acl-01 out switch(config-port-prof)# show port-profile name vm_eth1 port-profile vm_eth1 type: Vethernet description: status: enabled max-ports: 32 min-ports: 1 inherit: config attributes: ip port access-group acl-01 out no shutdown evaluated config attributes: ip port access-group acl-01 out no shutdown assigned interfaces: port-group: vm_eth1 system vlans: none capability l3control: no capability iscsi-multipath: no capability vxlan: no capability l3-vn-service: no port-profile role: none port-binding: static switch(config-port-prof)# copy running-config startup-config
Applying an IP ACL to the Management Interface
You can apply an IPv4 or ACL to the management interface, mgmt0.
Log in to the CLI in EXEC mode.
Be sure that the ACL that you want to apply exists and that it is configured to filter traffic in the manner that you need for this application.
| Command or Action | Purpose | |||
|---|---|---|---|---|
| Step 1 | switch# configure terminal |
Enters global configuration mode. | ||
| Step 2 | switch(config)# interface mgmt0 | Places you into interface configuration mode for the management interface. | ||
| Step 3 | switch(config-if)# [no] ip access-group access-list [in | out] | Applies a specified inbound or outbound IPv4 ACL to the interface. The no option removes the specified configuration. | ||
| Step 4 | switch(config-if)# show ip access-lists access-list | (Optional) Displays the ACL configuration. | ||
| Step 5 | switch(config-if)# [no] ip access-list match-local-traffic | The match-local-traffic option enables matching for locally-generated traffic.
| ||
| Step 6 | switch(config-if)# copy running-config startup-config | (Optional) Copies the running configuration to the startup configuration. |
This example shows how to apply an IP ACL to the management interface:
switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
switch(config)# ip access-list acl-01
switch(config-acl)# permit tcp any any
switch(config-acl)# show ip access-lists acl-01
IPV4 ACL acl-01
10 permit tcp any any
switch(config-acl)# interface mgmt 0
switch(config-if)# ip access-group acl-01 out
switch(config-if)# show ip access-lists acl-01 summary
IPV4 ACL acl-01
Total ACEs Configured:1
Configured on interfaces:
mgmt0 - egress (Router ACL)
Active on interfaces:
mgmt0 - egress (Router ACL)
switch(config-if)# ip access-list match-local-traffic
switch(config)# copy running-config startup-config
Configuring ACL Logging
ACL logging is enabled by default on all Virtual Ethernet Modules (VEMs). In addition, the following guidelines apply to ACL logging configuration:
- Disabling ACL Logging
- Configuring a Time Interval for Accumulating Packet Counters
- Configuring Flows
- Syslog Server Severity Levels
- Setting the Severity Level for a Syslog Message
Disabling ACL Logging
You can disable ACL logging on a VEM by entering the following command:
Command |
Purpose |
|---|---|
[no] logging ip access-list cache module vem |
Disables ACL logging on the specified VEM. |
Configuring a Time Interval for Accumulating Packet Counters
You can configure the time interval for accumulating packet counters before they are reported to the syslog servers. You enter the time range in seconds from 5 to 86,400 seconds (1 day). The default is 300 seconds (5 minutes).
You can configure the amount of time to accumulate packet counters by entering one of the following commands:
Command |
Purpose |
|---|---|
logging ip access-list cache interval secs |
Sets the time interval in seconds to accumulate packet counters before they are reported to the syslog servers, where secs is the number of seconds. |
[no] logging ip access-list cache interval secs |
Reverts the configuration to the default time interval configuration 300 seconds (5 minutes), where secs is the number of seconds. |
These examples show the time interval syslog message format that is sent periodically when the time interval expires:
ACL-LOGGING-6-PERMIT-FLOW-INTERVAL <VSM-id> <VEM-id> <protocol> <source-interface> <source-ip/source-port)> <destination-ip/destination-port> Hit-count = <nnn> ACL-LOGGING-6-DENY-FLOW-INTERVAL <VSM-id> <VEM-id> <protocol> <source-interface> <source-ip/source-port)> <destination-ip/destination-port> Hit-count = <nnn>
Configuring Flows
You can configure the number of deny and permit flows per VEM. The range is from 0 to 5000 flows. The default is 3000. A syslog message is sent when the flow is near the maximum threshold. The first message is sent when the number of flows has reached 75 percent of the maximum threshold and the next message is sent when the number of flows has reached 90 percent of the maximum threshold. The last message is sent when the number of flows reaches the maximum threshold of 100 percent.
Configuring Permit Flows
You can configure permit flows by entering one of the following commands:
Command |
Purpose |
|---|---|
logging ip access-list cache max-permit-flows num |
Sets the number of permit flows where num is the number of flows. |
[no] logging ip access-list cache max-permit-flows |
Reverts the configuration to the default permit flow value 3000. |
These examples show permit flow syslog messages:
New flow notification message:
- Aug 28 04:17:19 fish-231-157.cisco.com 1 2011-08-28T11:14:23 - n1k-ecology - ACLLOG-PERMIT-FLOW-CREATE VSM ID: 172.23.231.150, VEM ID: 86d04494-79e2-11df-a573-d0d0fd093c68, Source IP: 192.168.231.22, Destination IP: 192.168.231.21, Source Port: 42196, Destination Port: 8029, Source Interface: Veth2, Protocol: "TCP"(6), Hit-count = 1
Periodic flow reporting message:
- Aug 28 04:17:20 sfish-231-157.cisco.com 1 2011-08-28T11:14:23 - n1k-acllog – ACLLOG-PERMIT-FLOW-INTERVAL VSM ID: 172.23.231.150, VEM ID: 86d04494-79e2-11df-a573-d0d0fd093c68, Source IP: 192.168.231.22, Destination IP: 192.168.231.21, Source Port: 42196, Destination Port: 8029, Source Interface: Veth2, Protocol: "TCP"(6), Hit-count = 1245
Threshold crossing alarm messages:
- Aug 28 04:17:22 sfish-231-157.cisco.com 1 2011-08-28T11:14:24 - n1k-acllog - ACLLOG-MAX-PERMIT-FLOW-REACHED The number of ACL log permit-flows has reached 75 percent limit (3969) - Aug 28 04:17:26 sfish-231-157.cisco.com 1 2011-08-28T11:14:26 - n1k-acllog - ACLLOG-MAX-PERMIT-FLOW-REACHED The number of ACL log permit-flows has reached 90 percent limit (4969) - Aug 28 04:17:27 sfish-231-157.cisco.com 1 2011-08-28T11:14:31 - n1k-acllog - ACLLOG-MAX-PERMIT-FLOW-REACHED The number of ACL log permit-flows has reached 100 percent limit (5000)
Configuring Deny Flows
You can configure deny flows by entering one of the following commands:
Command |
Purpose |
|---|---|
logging ip access-list cache max-deny-flows num |
Sets the number of deny flows, where num is the number of flows. |
[no] logging ip access-list cache max-deny-flows |
Reverts the configuration back to the default deny flow value 3000. |
These examples show deny flow syslog messages:
New flow notification message
- Aug 28 04:17:19 sfish-231-157.cisco.com 1 2011-08-28T11:14:23 - n1k-acllog - ACLLOG-DENY-FLOW-CREATE VSM ID: 172.23.231.150, VEM ID: 86d04494-79e2-11df-a573-d0d0fd093c68, Source IP: 192.168.231.22, Destination IP: 192.168.231.100, Source Port: 48528, Destination Port: 8029, Source Interface: Veth2, Protocol: "TCP"(6), Hit-count = 1
Periodic flow reporting message
- Aug 28 04:17:20 sfish-231-157.cisco.com 1 2011-08-28T11:14:23 - n1k-acllog - ACLLOG-DENY-FLOW-INTERVAL VSM ID: 172.23.231.150, VEM ID: 86d04494-79e2-11df-a573-d0d0fd093c68, Source IP: 192.168.231.22, Destination IP: 192.168.231.100, Source Port: 47164, Destination Port: 8029, Source Interface: Veth2, Protocol: "TCP"(6), Hit-count = 1245
Threshold crossing alarm messages
- Aug 28 04:17:27 sfish-231-157.cisco.com 1 2011-08-28T11:14:31 - n1k-acllog - ACLLOG-MAX-DENY-FLOW-REACHED The number of ACL log deny-flows has reached 75 percent limit (4330) - Aug 28 04:18:27 sfish-231-157.cisco.com 1 2011-08-28T11:15:31 - n1k-acllog - ACLLOG-MAX-DENY-FLOW-REACHED The number of ACL log deny-flows has reached 90 percent limit (4630) - Aug 28 04:20:17 sfish-231-157.cisco.com 1 2011-08-28T11:17:20 - n1k-acllog - ACLLOG-MAX-PERMIT-FLOW-REACHED The number of ACL log permit-flows has reached 100 percent limit (5000)
Syslog Server Severity Levels
You can configure severity levels of the ACL logging syslog messages for up to three remote syslog servers. The range is from 0 to 7. The default severity level is 6.
Severity Code |
Severity Level |
Description |
|---|---|---|
0 |
Emergency |
System is unusable |
1 |
Alert |
Action must be taken immediately |
2 |
Critical |
Critical conditions |
3 |
Error |
Error conditions |
4 |
Warning |
Warning conditions |
5 |
Notice |
Normal but significant condition |
6 |
Informational |
informational messages |
7 |
Debug |
Debug-level messages |
Setting the Severity Level for a Syslog Message
You can set the severity level of a syslog message and the server to which you want the message to be sent by entering one of the following commands:
Command |
Purpose |
|---|---|
[no] acllog match-log-level level |
Sets the severity level at which syslog messages are sent, where level is the severity code from 0 to 7. The no acllog match-log-level level command will revert the ACL log level back to the default severity level 6. |
[no] logging ip access-list cache max-deny-flows number |
Sets the maximum number of deny flows to number per module. The no logging ip access-list cache max-deny-flows number sets the maximum number of deny-flows to default value of 3000. |
[ no] logging ip access-list cache max-permit-flows number |
Set the max-permit-flows to a specified number per module. The no logging ip access-list cache max-permit-flows number sets the maximum number of permit-flows to default value of 3000. |
logging server A.B.C.D 0-7 |
Specifies the syslog server on which you want to set a severity level, where A.B.C.D is the syslog server IP address and 0 to 7 are the severity levels you can choose. |
Note | For ACL logging to work, ACL Logging level should be equal or less than that of Syslog level. |
Verifying the IP ACL Configuration
Use one of the following commands to verify the configuration:
Command |
Purpose |
|---|---|
show running-config aclmgr |
Displays the ACL configuration, including the IP ACL configuration and interfaces that IP ACLs are applied to. |
show ip access-lists [name] |
Displays all IPv4 access control lists (ACLs) or a named IPv4 ACL. |
show ip access-list [name] summary |
Displays a summary of all configured IPv4 ACLs or a named IPv4 ACL. |
show running-config interface |
Displays the configuration of an interface to which you have applied an ACL. |
show logging ip access-list status |
Displays the ACL logging configuration for a VSM. |
vemcmd show acllog config |
Displays the VEM ACL logging configuration. |
Monitoring IP ACLs
Use one of the following commands for IP ACL monitoring:
Command |
Purpose |
|---|---|
show ip access-lists |
Displays the IPv4 ACL configuration. If the IPv4 ACL includes the statistics per-entry command, the show ip access-lists command output includes the number of packets that have matched each rule. |
clear ip access-list counters |
Clears statistics for all IPv4 ACLs or for a specific IPv4 ACL. |
Configuration Example for IP ACL
This example shows how to create an IPv4 ACL named acl-01 and apply it as a port ACL on physical ethernet interface which is not a member of port-channel and configuration verification with match counters:
switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
switch(config)# ip access-list acl-01
switch(config-acl)# permit ip 192.168.2.0/24 any
switch(config-acl)# permit ip 192.168.5.0/24 any
switch(config-acl)# permit 22 any 10.105.225.225/27
switch(config-acl)# permit ip any 10.105.225.225/27
switch(config-acl)# statistics per-entry
switch(config-acl)# interface ethernet 3/5
switch(config-if)# ip port access-group acl-01 in
switch(config-if)# show ip access-lists acl-01 summary
IPV4 ACL acl-01
statistics per-entry
Total ACEs Configured:4
Configured on interfaces:
Ethernet3/5 - ingress (Port ACL)
Active on interfaces:
Ethernet3/5 - ingress (Port ACL)
switch(config-if)# show ip access-lists acl-01
IPV4 ACL acl-01
statistics per-entry
100 permit ip 192.168.2.0/24 any [match=0]
110 permit ip 192.168.5.0/24 any [match=0]
120 permit 22 any 10.105.225.225/27 [match=0]
130 permit ip any 10.105.225.225/27 [match=44]
switch(config-if)# clear ip access-list counters acl-01
switch(config-if)# show ip access-lists acl-01
IPV4 ACL acl-01
statistics per-entry
100 permit ip 192.168.2.0/24 any [match=0]
110 permit ip 192.168.5.0/24 any [match=0]
120 permit 22 any 10.105.225.225/27 [match=0]
130 permit ip any 10.105.225.225/27 [match=0]
switch(config-if)#
This example shows how to enable access list matching for locally generated traffic:
switch# ip access-list match-local-traffic
This example shows how to verify VSM ACL logging configuration:
switch# show logging ip access-list status Max deny flows = 3000 Max permit flows = 3000 Alert interval = 300 Match log level = 6 VSM IP = 192.168.1.1 Syslog IP = 10.1.1.1 Syslog IP = 0.0.0.0 Syslog IP = 0.0.0.0 ACL Logging enabled on module(s): 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 ACL Logging disabled on module(s): 3
This example shows how to verify VEM ACL logging configuration:
switch# vemcmd show acllog config ACL-Log Config: Status: enabled Reporting Interval: 300 Max Permit Flows: 3000 Max Deny Flows: 3000 Syslog Facility : 4 Syslog Severity: 6 Syslog Srvr 1: 10.1.1.1 Syslog Srvr 2: 0.0.0.0 Syslog Srvr 3: 0.0.0.0 VSM: 192.168.1.1
Feature History for IP ACLs
This table only includes updates for those releases that have resulted in additions to the feature.
Feature History |
Releases |
Feature Information |
|---|---|---|
ACL Logging |
4.2(1)SV1(5.1) |
This feature was introduced. |
IP ACLs for mgmt0 interface |
4.2(1) SV1(4) |
This feature was introduced. |
IP ACLs |
4.0(4)SV1(1) |
This feature was introduced. |
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