Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Block internal IP

Does anyone know how to prevent people from knowing my Internal IP addresss on the Router ? I have created ACL deny all TCP traffic to my internal Network and applied it to Out Side Interface on the router. But it seems there is a program to find out your internal IP basing on header or something.

access-list 101 deny tcp any 172.16.0.0 0.0.255.255

Any advice would greatly be appreciated.

  • Other Security Subjects
2 REPLIES

Re: Block internal IP

You can use NAT to translate your source IP into a different IP. So your 172.16.0.0 network can look like 10.0.0.0. The create your acl to deny whatever you want (example all traffic originated on the outside and only allow return traffic to what your inside lan originated).

Hre is ageneral link about how NAT works: http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094831.shtml and a link with config examples: http://www.cisco.com/en/US/tech/tk648/tk361/tk438/tech_protocol_home.html

Hope it helps.

Steve

New Member

Re: Block internal IP

Thanks Steve

100
Views
0
Helpful
2
Replies
This widget could not be displayed.