Reference Guide

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] | log] [order] [monitor]
[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.
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, keep in mind that you might need to insert a
new filter. To prevent reconfiguring multiple filters, assign sequence numbers in multiples of five or
another number.
The following example 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 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]
[monitor] [fragments]
• Configure a deny or permit filter to examine TCP packets.
CONFIG-EXT-NACL mode
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Access Control Lists (ACLs)