Reference Guide

ip access-list standard access-listname
2. Configure a drop or forward filter.
CONFIG-STD-NACL mode
seq sequence-number {deny | permit} {source [mask] | any | host ip-address}
[count [byte]] [order] [fragments]
NOTE: When assigning sequence numbers to filters, keep in mind that you might need to insert a new filter. To
prevent reconfiguring multiple filters, assign sequence numbers in multiples of five.
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.
To view the rules of a particular ACL configured on a particular interface, use the show ip accounting
access-list ACL-name interface interface command in EXEC Privilege mode.
Example of Viewing the Rules of a Specific ACL on an Interface
FTOS#show ip accounting access-list ToOspf interface gig 1/6
Standard IP access list ToOspf
seq 5 deny any
seq 10 deny 10.2.0.0 /16
seq 15 deny 10.3.0.0 /16
seq 20 deny 10.4.0.0 /16
seq 25 deny 10.5.0.0 /16
seq 30 deny 10.6.0.0 /16
seq 35 deny 10.7.0.0 /16
seq 40 deny 10.8.0.0 /16
seq 45 deny 10.9.0.0 /16
seq 50 deny 10.10.0.0 /16
FTOS#
The following example shows how the seq command orders the filters according to the sequence number assigned. In
the example, filter 25 was configured before filter 15, but the show config command displays the filters in the correct
order.
Example of the seq Command to Order Filters
FTOS(config-std-nacl)#seq 25 deny ip host 10.5.0.0 any log
FTOS(config-std-nacl)#seq 15 permit tcp 10.3.0.0 /16 any
FTOS(config-std-nacl)#show config
!
ip access-list standard dilling
seq 15 permit tcp 10.3.0.0/16 any
seq 25 deny ip host 10.5.0.0 any log
FTOS(config-std-nacl)#
To delete a filter, use the no seq sequence-number command in IP ACCESS LIST mode.
Configuring a Standard IP ACL Filter
If you are creating a standard ACL with only one or two filters, you can let FTOS assign a sequence number based on the
order in which the filters are configured. The software assigns filters in multiples of five.
1. Configure a standard IP ACL and assign it a unique name.
CONFIGURATION mode
ip access-list standard access-list-name
2. Configure a drop or forward IP ACL filter.
CONFIG-STD-NACL mode
102