35. Configure Named Standard ACL
Named Standard ACL Scenario:
Do this on R3:
1. Allow network 201.52.60.0/24 to access R3
answer: permit 201.52.60.0 0.0.0.255
2. Allow network 192.168.16.0/24 to Access R3
answer: permit 192.168.16.0 0.0.0.255
3. Allow the entire network 192.168.14.0/24 to access R3, except these range of IP Addresses from 192.168.14.4/24 - 192.168.14.7/24.
we need to get the summary of the IP range first 192.168.14.4/24 - 192.168.14.7/24.
Summary: 192.168.14.4/30
answer: deny 192.168.14.1 0.0.0.3
answer: permit 192.168.14.0 0.0.0.255
4. Deny 192.168.13.5/24 IP Address to access R3.
we will add this rule using sequence number 15.
answer:
conf t
ip access-list standard std-rules
15 deny host 192.168.13.5
exit
5. Remove the summary IP 192.168.14.4/30 on the ACL rule
we will remove it using it's sequence number 30
answer:
conf t
ip access-list standard std-rules
no 30
exit
Standard ACL (Numbered) just for comparison on syntax:
conf t
access-list (acl# 1 - 199) permit/deny (source ip/net address) (wildcard mask)
Syntax:
conf t
ip access-list (standard/extended) (acl name)
Standard Named ACL
conf t
ip access-list standard (acl name)
permit/deny (source ip/net address) (wildcard mask)
Step 1: Create named standard ACL based in the scenario given.
R3:
conf t
ip access-list standard std-rules
permit 201.52.60.0 0.0.0.255
permit 192.168.16.0 0.0.0.255
deny 192.168.14.1 0.0.0.3
permit 192.168.14.0 0.0.0.255
exit
In Named ACL, we can easily modify the sequencing of the ACL rules. Example:
So with named standard ACL, it is easy to modify the rules without deletting / affecting the other rules not bound for changes
Step 2: Apply the ACL to an interface
R3:
conf t
interface se 0/1/1
! ip access-group (acl#acl name) in/out //syntax
ip access-group std-rules in
exit