Administrator Guide

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, UDP 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.
CONFIG-EXT-NACL mode
seq sequence-number {deny | permit} tcp {source mask | any | host ip-address} [count [byte]]
[order] [fragments]
When you create the filters with a specific sequence number, you can create the filters in any order and the filters are placed in the
correct order.
NOTE: When assigning sequence numbers to filters, you may have to insert a new filter. To prevent reconfiguring
multiple filters, assign sequence numbers in multiples of five or another number.
The example below shows how the seq command orders the filters according to the sequence number assigned. In the example, filter 15
was configured before filter 5, but the
show config command displays the filters in the correct order.
Dell(config-ext-nacl)#seq 15 deny ip host 112.45.0.0 any log
Dell(config-ext-nacl)#seq 5 permit tcp 12.1.3.45 0.0.255.255 any
Dell(config-ext-nacl)#show confi
!
ip access-list extended dilling
seq 5 permit tcp 12.1.0.0 0.0.255.255 any
seq 15 deny ip host 112.45.0.0 any log
Dell(config-ext-nacl)#
Configuring Filters Without a Sequence Number
If you are creating an extended ACL with only one or two filters, you can let the system assign a sequence number based on the order in
which the filters are configured. Filters are assigned in multiples of five.
To configure a filter for an extended IP ACL without a specified sequence number, use any or all of the following commands:
• Configure a deny or permit filter to examine IP packets.
CONFIG-EXT-NACL mode
{deny | permit} {source mask | any | host ip-address} [count [byte]] [order] [fragments]
• Configure a deny or permit filter to examine TCP packets.
CONFIG-EXT-NACL mode
{deny | permit} tcp {source mask] | any | host ip-address}} [count [byte]] [order]
[fragments]
• Configure a deny or permit filter to examine UDP packets.
CONFIG-EXT-NACL mode
{deny | permit} udp {source mask | any | host ip-address}} [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.
112
Access Control Lists (ACLs)