24-Port Layer 3 Switch Management Guide

A CCESS C ONTROL L IST C OMMANDS
4-81
- Both SYN and ACK valid, use “control-code 18 18”
- SYN valid and ACK invalid, use “control-code 2 18”
Example
This example accepts any incoming packets if the source address is within
subnet 10.7.1.x. For example, if the rule is matched; i.e., the rule (10.7.1.0
& 255.255.255.0) equals the masked address (10.7.1.2 & 255.255.255.0),
the packet passes through.
This allows TCP packets from class C addresses 192.168.1.0 to any
destination address when set for destination TCP port 80 (i.e., HTTP).
This permits all TCP packets from class C addresses 192.168.1.0 with the
TCP control code set to “SYN.”
Related Commands
access-list ip (4-76)
ip access-group
Use this command to bind a port to an IP ACL. Use the no form to
remove the port.
Syntax
ip access-group acl_name in
no ip access-group acl_name in
• acl_name – Name of the ACL. (Maximum length: 16 characters)
• in – Indicates that this list applies to input packets.
Console(config-ext-acl)#permit 10.7.1.1 255.255.255.0 any
Console(config-ext-acl)#
Console(config-ext-acl)#permit 192.168.1.0 255.255.255.0 any dport
80
Console(config-ext-acl)#
Console(config-ext-acl)#permit 192.168.1.0 255.255.255.0 any tcp
control-code 2 2
Console(config-ext-acl)#