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, ICMP Packets
To create a lter for ICMP packets with a specied sequence number, use the following commands.
1 Create either an extended IPv4 or IPv6 ACL and assign it a unique name.
CONFIGURATION mode
ip access-list extended access-list-name
ipv6 access-list extended access-list-name
2 Congure an extended IP ACL lter for ICMP packets.
CONFIG-EXT-NACL mode
seq sequence-number {deny | permit} icmp {source mask | any | host ip-address} [count [byte]]
[order] [monitor [session-id]] [fragments]
The ICMP packets cannot be ltered using mirroring ACL.
The following example shows the conguration to lter ICMP packets using IPv4 ACL:
DellEMC(config-ext-nacl)#show config
!
ip access-list extended icmp
seq 5 permit icmp any any echo count
seq 10 permit icmp any any echo-reply count
seq 15 permit icmp any any host-unreachable count
seq 20 permit icmp any any host-unknown count
seq 25 permit icmp any any network-unknown count
seq 30 permit icmp any any net-unreachable count
seq 35 permit icmp any any packet-too-big count
seq 40 permit icmp any any parameter-problem count
seq 45 permit icmp any any port-unreachable count
seq 50 permit icmp any any source-quench count
seq 55 permit icmp any any time-exceeded count
DellEMC(config-ext-nacl)#show ip accounting access-list
122
Access Control Lists (ACLs)