Concept Guide

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 [portnumber |
portname]] [count [byte]] [order] [monitor [session-id]] [fragments]
While conguring an IP access list, you can choose to congure either by using the logical name of the protocol or by using the port
number of the protocol. The logical names are available for both TCP and UDP.
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.
Example for conguring the IP access list using port numbers and protocol names:
DellEMC(config-ext-nacl)# seq 25 permit tcp any eq 40 any eq 33
DellEMC(config-ext-nacl)# seq 30 permit tcp any eq 33 any eq 43
DellEMC(config-ext-nacl)# seq 35 permit tcp any range www 194 any eq 101
DellEMC(config-ext-nacl)# seq 40 permit udp any eq 434 any gt mobile-ip
DellEMC(config-ext-nacl)# seq 45 deny udp any eq 53 any lt ntp
DellEMC(config-ext-nacl)#
DellEMC(config-ext-nacl)#show config
!
ip access-list extended vv
seq 25 permit tcp any eq 40 any eq 33
seq 30 permit tcp any eq 33 any eq 43
seq 35 permit tcp any range www 194 any eq 101
seq 40 permit udp any eq 434 any gt mobile-ip
seq 45 deny udp any eq 53 any lt ntp
Congure Filters, TCP Packets
To create a lter for TCP packets with a specied 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 Congure an extended IP ACL lter for TCP packets.
CONFIG-EXT-NACL mode
seq sequence-number {deny | permit} tcp {source mask | any | host ip-address} [count [byte]]
[order] [monitor [session-id]] [fragments]
Congure Filters, UDP Packets
To create a lter for UDP packets with a specied 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 Congure an extended IP ACL lter for UDP packets.
CONFIG-EXT-NACL mode
seq sequence-number {deny | permit} tcp {source mask | any | host ip-address} [count [byte]]
[order] [monitor [session-id]] [fragments]
Example of the seq Command
When you create the lters with a specic sequence number, you can create the lters in any order and the lters are placed in the correct
order.
Access Control Lists (ACLs)
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