Cisco




Cisco router - disconnect VTY user forcefully without reloading the router

Today's log. - Alert on a suspicious connection via ssh to the VTY line of the Cisco ISR 1100 router. - Logged in to the router, saw an established connection from IP belonging to Chinanet ISP (the router is in Israel) to the port 22. The router was compromised as someone removed …



Useful CLI commands for Cisco CUCM, Cisco Unity Connection and IM and Presence

Note: For quick reference, I put all the commands below as a cheat sheet PDF: Useful CLI commands for Cisco CUCM, Cisco Unity Connection and IM and Presence I don’t work on the command line of CUCM often, but when the need arises here is the short list of …



Cisco reflexive access-lists are still on CCNP Security exam

Today I was surprised to hear from someone who just took one of the CCNP Security exams that they still test for Reflexive access-lists - what a nostalgy. I was sure it has long been ousted by ip inspect and Zone Based Firewall, but no - it is still tested and still …



Cisco CUCM CDR report - call duration and called numbers extraction script

Yesterday I had to extract some data from a CDR report for a client, namely call start time, its duration and the called number. And while I am sure Google has zillion scripts to be found, it was much faster to hack this one-liner in AWK . The script extracts the …



How to enroll Cisco VPN client with IOS CA

It is worth mentioning that Cisco IOS routers can serve as CA servers as well. The example configurations are easy to find on the cisco.com (see link below). The only trick to know not stated in the documentation - when enrolling Cisco VPN client with IOS CA the syntax you …



'Archive IOS running configuration automatically for possible rollback '

Here is a feature that will save you time and frustration in many possible scenarios - especially when managing Cisco routers in multi-user environment. Once enabled archiving saves periodically copy of the running configuration of IOS router to the flash or remote server. So next time something stops working after changes …



Configure DVTI hairpinning on Cisco router for safe browsing

Today i am posting the video showing how to configure Dynamic Virtual Tunnel Interface (DVTI) on Cisco IOS router. DVTI for remote access has been available for a long time already and actually comes to gradually replace the old way of dynamic crypto maps, but as always people are hard …



Encrypting preshared keys stored on the cisco IOS router

You never know where your router may end up . It may be RMA'ed without proper wiping the configuration first, it may be plain simple stolen. In any of these or other unfortunate cases the last thing you would want is for the attacker get passwords or other security information stored …



Cisco router – how to schedule an unattended reload with EEM

Today a colleague of mine asked if I had a ready-to-use template to schedule a reload of Cisco IOS router . - "Of course, piece of cake, there should be millions of hits on it in Google" , was my thought. So, after 30 minutes of searching the mighty Google and being surprised …



Cisco Netflow performance data

Not much of a post but link to the Cisco site stating how much Netflow loads the Cisco routers: Netflow data sheet I, personally, do a lot of Netflow monitoring and can say that on unloaded routers , passing 2-5 mbits/sec of traffic, the additional load will be some 1-2 …