When working with the Cisco IOS, it’s very important to know your TCP and UDP port numbers. This is especially true when creating IOS access control lists (ACLs). Let’s take a closer look. What’s a ...

I'm having a problem with Cisco ACL's and DHCP. Whenever I turn on the ACL, the clients are unable to obtain DHCP IP addresses. I have a Cisco 7206 router with a T1 to a Cisco 2651 Router. The 2651 ...

HappyRouter.com has come across a free tool called the Cisco ACL Editor and Simulator. Developed by U.K. Cisco expert Gareth O. Evans, while he was studying at the Unversity of Wales, in North Wales, ...

I have a situation where I need to get a server setup that requires ACL's, then I need to move it to another subnet. I thought I'd try setting up DNS client on the router, as it is supported. Here are ...

While ICMP is required for IP network traffic redirection and pinging hosts on your LAN or WAN, ICMP can also pose a security concern. David Davis tells you about the basics of ICMP and how to filter ...