Cisco Routers – Port Forwarding
KB ID 0000533 Problem If you have a server or host that you want to be publicly addressable and only have one public IP address then port forwarding is what you require. Solution Assumptions 1. You have a public IP on the outside of your Router. 2. You are performing NAT from your internal range of IP address to your External IP address. To Make Sure 1. Run the following command: PetesRouter#show run | include ip nat inside You...
Cisco Router – CBAC and Zone Based Firewall Setup
KB ID 0000937 Problem IOS 11.2 gave us CBAC, and IOS 12.4(6)T gave us the Zone Based Firewall. You can still use either, (providing you are running the correct IOS, or in the case of version 15 and upwards, added the correct license, ‘securityK9’). For older IOS versions usually you want the advipservices version of the IOS). Solution Run the following command to see if you have the correct license installed....
Troubleshooting Phase 2 Cisco Site to Site (L2L) VPN Tunnels
KB ID 0000625 Problem It’s been over two years since I wrote Troubleshooting Phase 1 Cisco Site to Site (L2L) VPN Tunnels. I’ve always meant to come back and write the ‘Phase 2’ article but never got around to it. This article is NOT intended to be a ‘fix all” for phase 2 problems, it’s designed to point you in the right direction to locate the source of the problem. Solution Here’s my...
Cisco ASA 5500 – Deny a Single IP Address External Access
KB ID 0000743 Problem This got asked on Experts Exchange today, the poster specifically asked for an ASDM solution, so here goes. However I will also do the commands as well. Solution Block an IP via ASDM 1. Connect to the ASDM > Configuration > Firewall > Add ‘Network Object’. Note: You could create a Network Object Group, then add a Network Object to that group. This is handy if there are liable to be more IP...
Cisco ASA 5500 Allowing Tracert
KB ID 0000753 Problem I’d always assumed that as Tracert uses ICMP, and that simply adding ICMP inspection on the ASA would let Tracert commands work. A client of mine is having some comms problems and wanted to test comms from his remote DR site, he had enabled time-exceeded and unreachable on the ASA (for inbound traffic) and that had worked. I checked the default inspection map and found inspect ICMP was there? As it turns...