- Configuring Context-Based Access Control
- IPv6 IOS Firewall
- Cisco IOS Firewall Stateful Failover
- Configuring Port to Application Mapping
- Cisco IOS Firewall MIB
- Cisco IOS Firewall Performance Improvements
- Cisco IOS Firewall Support for TRP
- Firewall ACL Bypass
- Firewall Websense URL Filtering
- HTTP Inspection Engine
- Inspection of Router-Generated Traffic
- Transparent Cisco IOS Firewall
- Finding Feature Information
- Prerequisites Cisco IOS Firewall MIB
- Restrictions for Cisco IOS Firewall MIB
- Information About Cisco IOS Firewall MIB
- How to Configure Cisco IOS Firewall MIB
Cisco IOS Firewall MIB
The Cisco IOS Firewall MIB feature introduces support for the Cisco Unified Firewall MIB, which helps to manage and monitor firewall performance via Simple Network Management Protocol (SNMP). Statistics can be collected and monitored via standards-based SNMP techniques for firewall features such as stateful packet inspection and URL filtering.
- Finding Feature Information
- Prerequisites Cisco IOS Firewall MIB
- Restrictions for Cisco IOS Firewall MIB
- Information About Cisco IOS Firewall MIB
- How to Configure Cisco IOS Firewall MIB
- Configuration Examples for Cisco IOS Firewall MIB Monitoring
- Additional References
- Feature Information for Cisco IOS Firewall MIB
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.
Prerequisites Cisco IOS Firewall MIB
Before you can provide firewall connection and URL filtering statistics via SNMP, you must set up the firewall by performing the following tasks:
- Configure a firewall policy via the ip inspect name command.
- Enable the firewall by applying the firewall on a target via the interface command followed by the ip inspect command.
- Enable URL filtering, if applicable, via the ip urlfilter server vendor command.
You must also enable SNMP on the router. For more information on enabling SNMP, see the section "Enabling SNMP for Firewall Sessions" later in this document.
Restrictions for Cisco IOS Firewall MIB
- Cisco does not support all of the MIB variables that are defined in the Cisco Unified Firewall MIB. For a list of variables that are supported by this feature, see the table below.
- MIB statistics are not provided when the firewall is configured using CPL.
Memory and Performance Impact
Depending on the number of targets that have a configured firewall and the number of configured URL filtering servers, the MIB functionality can create an adverse impact on memory. For each firewall policy that is configured on your system, more memory is required to store SNMP statistics.
The following information defines the minimum memory requirements for connection statistics only:
- Global connection statistics: approximately 64 bytes.
- Protocol-specific statistics: multiply the number of configured protocols by 56 to determine the minimum memory requirement.
- Policy-target-protocol statistics: multiply the number of configured protocols and the number of targets for which the firewall policies are configured by 48 to determine the minimum memory requirement.
The following information defines the minimum memory requirements for URL filtering statistics only:
Information About Cisco IOS Firewall MIB
Connection Statistics
Connection statistics are a record of the firewall traffic streams that have attempted to flow through the firewall system. Connection statistics can be displayed on a global basis (that is, an aggregate of all connection statistics for the entire router), protocol-specific basis, or a firewall-policy-specific basis. The Firewall can allow, drop, or deny the connection based on firewall policies and firewall resources.
The table below lists all supported connection statistics--global, protocol-specific1, or firewall-policy-specific2--that are available via SNMP.
| Table 1 | Connection Statistics |
URL Filtering Statistics
URL Filtering feature provides an Internet management application that allows you to control web traffic for a given host or user on the basis of a specified security policy. URL filtering statistics include the status of distinct URL filtering servers that are configured on the firewall and the impact of the performance of the URL filtering servers on the latency and throughput of the firewall.
The tables below list all supported URL filtering statistics--on a global basis or per server--that are available via SNMP.
| Table 2 | Global URL Filtering Statistics (across all servers) |
| Connection Type |
Description |
|---|---|
| Five minute URL Filtering Requests Declined Rate |
Rate at which URL access requests were declined by the firewall via the URL filtering server or the firewall exclusive domain configuration, averaged over the last 300 seconds. |
| Five minute URL Filtering Requests Resource Dropped Rate |
Rate at which URL access requests were dropped by the firewall due to firewall resource constraints, averaged over the last 300 seconds. |
| One minute URL Filtering Requests Declined Rate |
Rate at which URL access requests were declined by the firewall via the URL filtering server or the firewall exclusive domain configuration, averaged over the last 60 seconds. |
| One minute URL Filtering Requests Resource Dropped Rate |
Rate at which URL access requests were dropped by the firewall due to firewall resource constraints, averaged over the last 60 seconds. |
| URL Filtering Allow Mode On |
Displays whether the firewall has allowed or discarded URL requests when the URL filtering server is not available. Returns a "true" statistics if the firewall allows all requested URLs to be retrieved from the remote host when the URL server is not available; returns a "false" statistic of the firewall discards all URL. |
| URL Filtering Allow Mode Requests Allowed |
Number of URL access requests that were allowed by the firewall when the URL filtering server was not available. |
| URL Filtering Allow Mode Requests Denied |
Number of URL access requests that were denied by the firewall when the URL filtering server was not available. |
| URL Filtering Enabled |
Displays whether or not URL filtering is enabled. Returns a "false" statistic if the firewall will not perform URL filtering, even if the system contains configuration information that pertains to other aspects of URL filtering. |
| URL Filtering Late Responses |
Number of responses from the URL filtering server that were received after the original URL access request was dropped by the Firewall. |
| URL Filtering Requests Allowed |
Number of URL access requests allowed by the firewall via the use of the URL filtering server or the firewall exclusive domain configuration. |
| URL Filtering Requests Declined |
Number of URL access requests that were declined by the firewall via the URL filtering server or the firewall exclusive domain configuration. |
| URL Filtering Requests Processed |
Number of URL access requests that were processed by the firewall. |
| URL Filtering Request Process Rate |
Number of URL access requests that were processed per second by the firewall, averaged over the last 300 seconds. |
| URL Filtering Requests Resource Dropped |
Number of incoming URL access requests that were dropped by the Firewall due to firewall resource constraints. |
| URL Filtering Responses Resource Dropped |
Number of responses to URL access requests from remote hosts that were dropped by the firewall due to resource constraints while the firewall was waiting for a response from the URL filtering server. |
| URL Filtering Server Timeouts |
Number of times the firewall did not receive a response from the URL Filtering server. |
| Table 3 | Per server URL Filtering Statistics |
| Connection Type |
Description |
|---|---|
| URL Filtering Protocol Version |
Version of the transport protocol that is used by the firewall to communicate with the URL filtering server. For TCP, valid version values are 1 and 4. For UDP, 1 is the only valid version. |
| URL Filtering Server Late Responses |
Number of URL access responses received by the firewall from the URL filtering server after the original URL access request was dropped by the firewall. |
| URL Filtering Server Requests |
Number of URL access requests forwarded by the firewall to the URL filtering server. |
| URL Filtering Server Requests Allowed |
Number of URL access requests allowed by the URL filtering server. The count does not include late responses. |
| URL Filtering Server Requests Declined |
Number of URL access requests declined by the URL filtering server. The count does not include late responses. |
| URL Filtering Server Responses |
Number of URL access responses received by the firewall from the URL filtering server. The count does not include late responses. |
| URL Filtering Server Response Time Rate |
Average round-trip response time of the URL filtering server, averaged over the last 300 seconds. A value of zero indicates that there was insufficient data to compute this value over the last time interval. |
| URL Filtering Server Status |
Status of the URL filtering server: ONLINE or OFFLINE. |
| URL Filtering Server Timeouts |
Number of times the URL filtering server failed to respond to URL access requests sent by the firewall. |
| URL Filtering Server Transport Protocol |
Transport protocol that is used by the firewall to communicate with the URL filtering server. The protocol will be TCP, UDP, or DEFAULT. DEFAULT is used in implementations that do not explicitly specify a transport protocol. |
| URL Filtering Server Vendor |
Vendor who provided the URL filtering server. Currently only Websense and N2H2 servers are supported. |
A URL filtering server is identified by the following items, which also form the indexes into the URL filtering server statistics table:
Firewall MIB Traps
To receive firewall MIB traps, you need a management station, and you must enable the snmp-server enable trap firewall serverstatuschange command (as shown in the configuration task table below).
Output for the SNMP trap fields, which are displated in on the management station, are as follows:
- Server IP Address Type (IPv4 or IPv6)
- Server IP Address Type Length. (4 for IPv4 and 16 for IPv6)
- Server IP Address
- Server Port
![]() Note |
Only IPv4 is currently supported. |
How to Configure Cisco IOS Firewall MIB
Enabling SNMP for Firewall Sessions
Perform this task to enable SNMP for firewall-related session management.
Before you can begin monitoring firewall performance via SNMP, you must set up the firewall by performing the following tasks:
- Configure a firewall policy via the ip inspect name command.
![]() Note |
Statistics are collected only for protocols that are specified via the ip inspect name command. |
- Enable the firewall by applying the firewall on a target via the interface command followed by the ip inspect command.
- Enable URL filtering, if applicable, via the ip urlfilter server vendor command.
DETAILED STEPS
What to Do Next
After the firewall and SNMP have been properly enabled, statistics will begin to accumulate after the traffic flow starts. To verify whether statistics are being collected and view MIB counters, you can perform at least one of the steps in the task "Verifying Firewall Connection and URL Filtering Statistics."
Verifying Firewall Connection and URL Filtering Statistics
Use this task to verify firewall connection and URL filtering statistics via command-line interface (CLI). (These statistics can also be collected via any SNMP-capable client.)
![]() Note |
Effective with Cisco IOS Release 12.4(20)T, the debug ip inspect command is replaced by the debug policy-firewall command. See the Cisco IOS Debug Command Reference for more information. |
DETAILED STEPS
Troubleshooting Tips
All statistics are accumulated since the last reboot of the firewall system. Thus, you must reboot the system to clear MIB connection statistics from your system.
Configuration Examples for Cisco IOS Firewall MIB Monitoring
- Example Sample Cisco IOS Firewall Configuration
- Example Sample URL Filtering Configuration
- Example show ip inspect mib Output
- Example show ip urlfilter mib statistics command output
Example Sample Cisco IOS Firewall Configuration
The following output from the show running-config command shows how to configure a Cisco IOS Firewall:
Router# show running-config
Building configuration...
Current configuration : 2205 bytes
!
version 12.4
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
service internal
!
hostname Router
!
boot-start-marker
boot-end-marker
!
no logging console
!
no aaa new-model
!
resource policy
!
clock timezone MST -8
clock summer-time MDT recurring
no ip cef
!
!
!
!
ip inspect name test tcp
ip inspect name test udp
ip inspect name test icmp timeout 30
ip inspect name test ftp
ip inspect name test http
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
policy-map ratelimit
class class-default
police cir 10000000
conform-action transmit
exceed-action drop
!
!
!
!
!
!
!
interface FastEthernet0/0
ip address 192.168.27.2 255.255.255.0
ip access-group 101 out
ip inspect test in
duplex full
service-policy input ratelimit
!
interface FastEthernet1/0
no ip address
no ip route-cache
shutdown
duplex half
!
interface FastEthernet4/0
ip address 192.168.127.2 255.255.255.0
ip access-group 102 in
duplex full
service-policy input ratelimit
!
router eigrp 100
network 192.168.27.0
network 192.168.127.0
no auto-summary
no eigrp log-neighbor-changes
no eigrp log-neighbor-warnings
!
ip default-gateway 192.168.27.116
ip route 192.168.100.0 255.255.255.0 192.168.27.1
ip route 192.168.200.0 255.255.255.0 192.168.127.1
no ip http server
no ip http secure-server
!
!
!
logging alarm informational
access-list 101 permit tcp any any fragments
access-list 101 permit udp any any fragments
access-list 101 deny tcp any any
access-list 101 deny udp any any
access-list 101 permit ip any any
access-list 102 permit tcp any any fragments
access-list 102 permit udp any any fragments
access-list 102 permit udp any gt 1024 any eq snmp
access-list 102 deny tcp any any
access-list 102 deny udp any any
access-list 102 permit ip any any
snmp-server community public RO
snmp-server location FW Testbed UUT
snmp-server contact STG/IOS FW Devtest
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
gatekeeper
shutdown
!
!
line con 0
exec-timeout 0 0
stopbits 1
line aux 0
stopbits 1
line vty 0 4
login
!
exception core-file sisu-devtest/coredump/Router.core
exception dump 192.168.27.116
!
end
Example Sample URL Filtering Configuration
The following sample output from the show running-config command shows how to configure a Websense server for URL filtering:
Router# show running-config Building configuration... Current configuration : 2043 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption service internal ! hostname Router ! boot-start-marker boot-end-marker ! no logging console ! no aaa new-model ! resource policy ! clock timezone MST -8 clock summer-time MDT recurring no ip cef ! ! ip inspect name test tcp ip inspect name test udp ip inspect name test http urlfilter ! ! ip urlfilter allow-mode on ip urlfilter exclusive-domain deny www.cnn.com ip urlfilter exclusive-domain permit www.cpp.com ip urlfilter server vendor websense 192.168.29.116 ! ! ! ! ! ! ! ! ! interface FastEthernet0/0 ip address 192.168.29.2 255.255.255.0 ip access-group 101 out ip inspect test in speed auto full-duplex ! interface FastEthernet0/1 ip address 192.168.129.2 255.255.255.0 ip access-group 102 in duplex auto speed auto ! router eigrp 100 network 192.168.29.0 network 192.168.129.0 no auto-summary no eigrp log-neighbor-changes no eigrp log-neighbor-warnings ! ip default-gateway 192.168.28.116 ip route 192.168.100.0 255.255.255.0 192.168.29.1 ip route 192.168.200.0 255.255.255.0 192.168.129.1 ! ! ip http server no ip http secure-server ! access-list 101 permit tcp any any fragments access-list 101 permit udp any any fragments access-list 101 deny tcp any any access-list 101 deny udp any any access-list 101 permit ip any any access-list 102 permit tcp any any fragments access-list 102 permit udp any any fragments access-list 102 permit udp any gt 1024 any eq snmp access-list 102 deny tcp any any access-list 102 deny udp any any access-list 102 permit ip any any snmp-server community public RO snmp-server location FW Testbed UUT snmp-server contact STG/IOS FW Devtest ! ! ! ! control-plane ! ! ! line con 0 exec-timeout 0 0 transport output all line aux 0 transport output all line vty 0 4 login ! exception core-file sisu-devtest/coredump/Router.core exception dump 192.168.28.116 ! webvpn context Default_context ssl authenticate verify all ! no inservice ! ! end
Example show ip inspect mib Output
The following examples are sample outputs from the show ip inspect mibcommand with global or protocol-specific keywords:
Global MIB Statistics
Router# show ip inspect mib connection-statistics global
--------------------------------------------------
Connections Attempted 7
Connections Setup Aborted 0
Connections Policy Declined 0
Connections Resource Declined 0
Connections Half Open 2 Connections Active 3
Connections Expired 2
Connections Aborted 0
Connections Embryonic 0
Connections 1-min Setup Rate 5
Connections 5-min Setup Rate 7
Protocol-Based MIB Statistics
Router# show ip inspect mib connection-statistics l4-protocol tcp -------------------------------------------------- Protocol tcp Connections Attempted 3 Connections Setup Aborted 0 Connections Policy Declined 0 Connections Resource Declined 0 Connections Half Open 1 Connections Active 2 Connections Aborted 0 Connections 1-min Setup Rate 3 Connections 5-min Setup Rate 3 Router# show ip inspect mib connection-statistics l7-protocol http -------------------------------------------------- Protocol http Connections Attempted 3 Connections Setup Aborted 0 Connections Policy Declined 2 Connections Resource Declined 0 Connections Half Open 0 Connections Active 1 Connections Aborted 0 Connections 1-min Setup Rate 1 Connections 5-min Setup Rate 2
Policy-Target-Based MIB Statistics
Router# show ip inspect mib connection-statistics policy ftp interface GigabitEthernet0/0 l4-protocol tcp ! Policy Target Protocol Based Connection Summary Stats ------------------------------------------------------ Policy ftp-inspection Target GigabitEthernet0/0 Protocol tcp Connections Attempted 3 Connections Setup Aborted 0 Connections Policy Declined 0 Connections Resource Declined 0 Connections Half Open 1 Connections Active 2 Connections Aborted 0 Router# show ip inspect mib connection-statistics policy ftp interface GigabitEthernet0/0 l7-protocol ftp ! Policy Target Protocol Based Connection Summary Stats ------------------------------------------------------ Policy ftp-inspection Target GigabitEthernet0/0 Protocol ftp Connections Attempted 3 Connections Setup Aborted 0 Connections Policy Declined 0 Connections Resource Declined 0 Connections Half Open 1 Connections Active 2 Connections Aborted 0
Example show ip urlfilter mib statistics command output
The following example is sample output when MIBs are enabled to track URL filtering statistics across the entire device (global):
Router# show ip urlfilter mib statistics global
URL Filtering Group Summary Statistics
------------------------------------------------------
URL Filtering Enabled
Requests Processed 260
Requests Processed 1-minute Rate 240
Requests Processed 5-minute Rate 215
Requests Allowed 230
Requests Denied 30
Requests Denied 1-minute Rate 15
Requests Denied 5-minute Rate 0
Requests Cache Allowed 5
Requests Cache Denied 5
Allow Mode Requests Allowed 15
Allow Mode Requests Denied 15
Requests Resource Dropped 0
Requests Resource Dropped 1-minute Rate 0
Requests Resource Dropped 5-minute Rate 0
Server Timeouts 0
Server Retries 0
Late Server Responses 0
Access Responses Resource Dropped 0
The following example is sample output when MIBs are enabled to track URL filtering statistics across the server with IP address 192.168.27.116:
Router# show ip urlfilter mib statistics server address 192.168.27.116
URL Filtering Server Statistics
------------------------------------------------------
URL Server Host Name 192.168.27.116
Server Address 192.168.27.116
Server Port 15868
Server Vendor Websense
Server Status Online
Requests Processed 4
Requests Allowed 1
Requests Denied 3
Server Timeouts 0
Server Retries 9
Responses Received 1
Late Server Responses 12
1 Minute Average Response Time 0
5 Minute Average Response Time 0
Additional References
Related Documents
| Related Topic |
Document Title |
|---|---|
| Cisco IOS commands |
|
| Security commands |
Cisco IOS Security Command Reference |
| Description of SNMP, SNMP MIBs, and how to configure SNMP on Cisco devices |
"Configuring SNMP Support" |
| Description of Cisco IOS firewalls and functions such as how to configure a firewall and URL filtering |
"Configuring Context-based Access Control" |
Standards
| Standard |
Title |
|---|---|
| None |
-- |
MIBs
| MIB |
MIBs Link |
|---|---|
| To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
RFCs
| RFC |
Title |
|---|---|
| None |
-- |
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. |
Feature Information for Cisco IOS Firewall MIB
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 4 | Feature Information for Cisco IOS Firewall MIB |
| Feature Name |
Releases |
Feature Information |
|---|---|---|
| Cisco IOS Firewall MIB |
12.4(6)T |
Introduces support for the Cisco Unified Firewall MIB, which helps to manage and monitor firewall performance via SNMP. Statistics can be collected and monitored via standards-based SNMP techniques for firewall features such as stateful packet inspection and URL filtering. The following commands were introduced or modified: debug ip inspect, show ip inspect, show ip urlfilter statistics, snmp-server enable traps firewall. |
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

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