Chapter 10
| Access Control Lists
IPv4 ACLs
– 322 –
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.
Console(config-ext-acl)#permit 10.7.1.1 255.255.255.0 any
Console(config-ext-acl)#
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).
Console(config-ext-acl)#permit 192.168.1.0 255.255.255.0 any destination-port
80
Console(config-ext-acl)#
This permits all TCP packets from class C addresses 192.168.1.0 with the
TCP control code set to “SYN.”
Console(config-ext-acl)#permit tcp 192.168.1.0 255.255.255.0 any control-
flag 2 2
Console(config-ext-acl)#
Related Commands
access-list ip (318)
Time Range (145)
ip access-group
This command binds an IPv4 ACL to a port. Use the
no
form to remove the
port.
Syntax
ip access-group
acl-name
in
[
time-range
time-range-name
] [
counter
]
no ip access-group
acl-name
in
acl-name
– Name of the ACL. (Maximum length: 32 characters)
in
– Indicates that this list applies to ingress packets.
time-range-name
- Name of the time range. (Range: 1-32
characters)
counter
– Enables counter for ACL statistics.
Default Setting
None
