Configure an Extended IP ACL
Extended IP ACLs filter on source and destination IP addresses, IP host addresses, TCP addresses, TCP
host addresses, UDP addresses, and UDP host addresses.
Because traffic passes through the filter in the order of the filter’s sequence, you can configure the
extended IP ACL by first entering IP ACCESS LIST mode and then assigning a sequence number to the
filter.
Configuring Filters with a Sequence Number
To configure filters with a sequence number, use the following commands.
1. Enter IP ACCESS LIST mode by creating an extended IP ACL.
CONFIGURATION mode
ip access-list extended access-list-name
2. Configure a drop or forward filter.
CONFIG-EXT-NACL mode
seq sequence-number {deny | permit} {ip-protocol-number | icmp | ip | tcp |
udp} {source mask | any | host ip-address} {destination mask | any | host
ip-address} [operator port [port]] [count [byte]] [order] [fragments]
When you use the log keyword, the CP logs details about the packets that match. Depending on how
many packets match the log entry and at what rate, the CP may become busy as it has to log these
packets’ details.
Configure Filters, TCP Packets
To create a filter for TCP packets with a specified sequence number, use the following commands.
1. Create an extended IP ACL and assign it a unique name.
CONFIGURATION mode
ip access-list extended access-list-name
2. Configure an extended IP ACL filter for TCP packets.
CONFIG-EXT-NACL mode
seq sequence-number {deny | permit} tcp {source mask | any | host ip-
address}} [count [byte]] [order] [fragments]
Configure Filters, TCP Packets
To create a filter for UDP packets with a specified sequence number, use the following commands.
1. Create an extended IP ACL and assign it a unique name.
CONFIGURATION mode
ip access-list extended access-list-name
2. Configure an extended IP ACL filter for UDP packets.
100 Access Control Lists (ACLs)