I'm setting up a number of vpn/ipsec tunnels on a cisco 876.
When I enter the necessary acl's, I get no error, but when I check my running config, the router seems to have altered the acl.
Here's what happens:
Router(config)#access-list 111 remark *** Tunnel naar Takman Ommen ***
Router(config)#access-list 111 permit ip 192.168.26.0 255.255.255.0 192.168.28.0 255.255.255.0
Extended IP access list 111
10 permit ip 0.0.0.0 255.255.255.0 0.0.0.0 255.255.255.0
Running the Version 12.4(15)T1.
I have seen this behavior and as said above it is due to the use of subnet masks instead of inverse wildcard masks while defining the access-list
These are common errors particularly if you are used to work on PIX/ASA where we do not use inverse masks
Simply you are not matching any specific criteria here, looking at your config:-
permit ip 192.168.26.0 255.255.255.0 192.168.28.0 255.255.255.0
you are saying (I dont care about 192.168.26 at your ACL), its not a subnet mask equation, but rather its a wildcard bits match.
The correct one as bellow:
access-list 111 permit ip 192.168.26.0 0.0.0.255 192.168.28.0 0.0.0.255