Dell S4820T, Configuration Manual

Page: 140 / 1178

Configuring Filters Without a Sequence Number
If you are creating an extended ACL with only one or two filters, you can let Dell Networking OS assign a
sequence number based on the order in which the filters are configured. Dell Networking OS assigns
filters 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.
The following example shows an extended IP ACL in which the sequence numbers were assigned by the
software. The filters were assigned sequence numbers based on the order in which they were configured
(for example, the first filter was given the lowest sequence number). The
show config
command in IP
ACCESS LIST mode displays the two filters with the sequence numbers 5 and 10.
Example of Viewing Filter Sequence for a Specified Extended ACL
Dell(config-ext-nacl)#deny tcp host 123.55.34.0 any
Dell(config-ext-nacl)#permit udp 154.44.123.34 0.0.255.255 host 34.6.0.0
Dell(config-ext-nacl)#show config
!
ip access-list extended nimule
seq 5 deny tcp host 123.55.34.0 any
seq 10 permit udp 154.44.0.0 0.0.255.255 host 34.6.0.0
Dell(config-ext-nacl)#
To view all configured IP ACLs and the number of packets processed through the ACL, use the
show ip
accounting access-list
command in EXEC Privilege mode, as shown in the first example in
Configure a Standard IP ACL Filter .
140
Access Control Lists (ACLs)