To delete a filter, enter the show config command in IP ACCESS LIST mode and locate the sequence number of the filter you want todelete. Then use the no seq sequence-number command in IP ACCESS LIST mode.Configure an Extended IP ACLExtended IP ACLs filter on source and destination IP addresses, IP host addresses, TCP addresses, TCP host addresses, UDP addresses,and UDP host addresses.The traffic passes through the filter in the order of the filter’s sequence and hence you can configure the extended IP ACL by first enteringIP ACCESS LIST mode, and then assigning a sequence number to the filter.Configuring Filters with a Sequence NumberTo configure filters with a sequence number, use the following commands.1 Enter IP ACCESS LIST mode by creating an extended IP ACL.CONFIGURATION modeip access-list extended access-list-name2 Configure a drop or forward filter.CONFIG-EXT-NACL modeseq 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 configuring an IP access list, you can choose to configure either by using the logical name of the protocol or by using the portnumber 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 entryand at what rate, the CP may become busy as it has to log these packets’ details.Example for configuring the IP access list using port numbers and protocol names:Dell(config-ext-nacl)# seq 25 permit tcp any eq 40 any eq 33Dell(config-ext-nacl)# seq 30 permit tcp any eq 33 any eq 43Dell(config-ext-nacl)# seq 35 permit tcp any range www 194 any eq 101Dell(config-ext-nacl)# seq 40 permit udp any eq 434 any gt mobile-ipDell(config-ext-nacl)# seq 45 deny udp any eq 53 any lt ntpDell(config-ext-nacl)#Dell(config-ext-nacl)#show config!ip access-list extended vvseq 25 permit tcp any eq 40 any eq 33seq 30 permit tcp any eq 33 any eq 43seq 35 permit tcp any range www 194 any eq 101seq 40 permit udp any eq 434 any gt mobile-ipseq 45 deny udp any eq 53 any lt ntpConfigure Filters, ICMP PacketsTo create a filter for ICMP packets with a specified sequence number, use the following commands.1 Create either an extended IPv4 or IPv6 ACL and assign it a unique name.CONFIGURATION modeip access-list extended access-list-nameAccess Control Lists (ACLs) 121
