To control access to an interface, use the ipv4 access-group command in an appropriate configuration mode. To remove the specified access group, use the no form of this command.
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the ipv4 access-group command to control access to an interface. To remove the specified access group, use the no form of the command. Use the access-list-name argument to specify a particular IPv4 access list. Use the ingress keyword to filter on inbound packets or the egress keyword to filter on outbound packets. Use the hardware-count argument to enable hardware counters for the access group.
Permitted packets are counted only when hardware counters are enabled using the hardware-count argument. Denied packets are counted whether hardware counters are enabled or not.
To enter the dynamic template configuration mode, run dynamic-template command in the global configuration mode.
Under the dynamic template configuration mode, only the egress and ingress keywords are displayed.
For packet filtering applications using the ipv4/ipv6 access-group command, packet counters are maintained in hardware for each direction. If an access group is used on multiple interfaces in the same direction, then packets are counted for each interface that has the hardware-count argument enabled.
If the access list permits the addresses, the software continues to process the packet. If the access list denies the address, the software discards the packet and returns an Internet Control Message Protocol (ICMP) host unreachable message.
If the specified access list does not exist, all packets are passed.
By default, the unique or per-interface ACL statistics are disabled.
This is an example of the show access-lists command:
RP/0/RSP0/CPU0:router# show access-lists
ipv4 access-list acl-common
10 permit ipv4 host 18.104.22.168 host 22.214.171.124 log-input
15 deny ipv4 any host 126.96.36.199
20 permit ipv4 host 188.8.131.52 host 184.108.40.206 log-input
25 deny ipv4 any host 220.127.116.11
30 permit ipv4 host 18.104.22.168 host 22.214.171.124 log-input
35 deny ipv4 any host 126.96.36.199
ipv4 access-list acl-unique1
10 permit ipv4 host 188.8.131.52 host 184.108.40.206 log-input
15 deny ipv4 any host 220.127.116.11
20 permit ipv4 any any
ipv4 access-list ssm-acl
10 permit ipv4 18.104.22.168 0.255.255.255 any log
This is an example of a configured IPv4 ACL in the dynamic template configuration mode:
RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv4 access-group a1 egress