Reference Guide
Assign sequence number to lter
IP ACLs lter on source and destination IP addresses, IP host addresses, TCP addresses, TCP host addresses, UDP addresses, and UDP
host addresses. Trac passes through the lter by lter sequence. Congure the IP ACL by rst entering IP ACCESS-LIST mode and then
assigning a sequence number to the lter.
User-provided sequence number
• Enter IP ACCESS LIST mode by creating an IP ACL in CONFIGURATION mode.
ip access-list access-list-name
• Congure a drop or forward lter in IPV4-ACL mode.
seq sequence-number {deny | permit | remark} {ip-protocol-number | icmp | ip | protocol | tcp
| udp} {source prefix | source mask | any | host} {destination mask | any | host ip-address}
[count [byte]] [fragments]
Auto-generated sequence number
If you are creating an ACL with only one or two lters, you can let the system assign a sequence number based on the order in which you
congure the lters. The system assigns sequence numbers to lters using multiples of ten values.
• Congure a deny or permit lter to examine IP packets in IPV4-ACL mode.
{deny | permit} {source mask | any | host ip-address} [count [byte]] [fragments]
• Congure a deny or permit lter to examine TCP packets in IPV4-ACL mode.
{deny | permit} tcp {source mask] | any | host ip-address}} [count [byte]] [fragments]
• Congure a deny or permit lter to examine UDP packets in IPV4-ACL mode.
{deny | permit} udp {source mask | any | host ip-address}} [count [byte]] [fragments]
Assign sequence number to lter
OS10(config)# ip access-list acl1
OS10(conf-ipv4-acl)# seq 5 deny tcp any any capture session 1 count
View ACLs and packets processed through ACL
OS10# show ip access-lists in
Ingress IP access-list acl1
Active on interfaces :
ethernet1/1/5
seq 5 permit ip any any count (10000 packets)
L2 and L3 ACLs
Congure both L2 and L3 ACLs on an interface in L2 mode. Rules apply if you use both L2 and L3 ACLs on an interface.
• L3 ACL lters packets and then the L2 ACL lters packets
• Egress L3 ACL lters packets
Rules apply in order:
• Ingress L3 ACL
• Ingress L2 ACL
• Egress L3 ACL
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Access Control Lists