Tips - Whispers in the Wires

Whispers in the Wires

Tips

A collection of 3 posts

Use of “no dns lookup” vs “transport preferred none” on Cisco IOS

Use of “no dns lookup” vs “transport preferred none” on Cisco IOS

I was just having a discussion on one of Orhan Ergun’s posts on LinkedIn about “no dns lookup” vs “transport preferred none” in a #Cisco #IOS configuration. I thought it deserved a wider distribution, so here I am. Lots of folks disable name lookups on Cisco IOS boxen to

Generate IOS SSH Server Keys on Startup

Generate IOS SSH Server Keys on Startup

When working with Cisco IOS, I use the following EEM script to generate the SSH key on reload if there isn't one present already.

Simplified NAT

Originally published as "Curbing the Evil of NAT (in IOS)" Introduction NAT is a necessary evil. It is necessary because the IPv4 address space would have been exhausted before the end of the 20th century and it can be argued that the Internet as we know it today would never