Netmasks on Cisco Routers

[KevinGreene]

Hi:

I was recently provided a /25 from my Tier 1 provider. I have not had an issue in the past configuring my Cisco routers with a /24 but for the life of me, I can not get the netmask to work correctly on a /25.

I was given the upper half of a /25 (.128 to .255).

I added this for the ACL (I have removed much of the ACL for bevity).

This is what I was expecting:

permit tcp any x.x.x.128 0.0.0.128 established
deny ip x.x.x.128 0.0.0.128 any log-input

But the router seems to see the lower part only:

But in the router, it is seen as:

permit tcp any x.x.x.0 0.0.0.128 established
deny ip x.x.x.0 0.0.0.128 any log-input

Somewhere, I must have a mental defect... The netmask is .128 for sure.

Thanks for any help.

Kevin

 

[Cluebird]

Your wildcard mask is incorrect. It should be 0.0.0.127.

permit tcp any x.x.x.0 0.0.0.127 established
deny ip x.x.x.0 0.0.0.127 any log