Sniffing traffic punted to CPU on Cisco 6500

Submitted by cliff on Wed, 21/03/2018 - 10:57

Sometimes your Cisco 6500 seems to having a hard time with high CPU. Most cases are pretty obvious, like rancid or librenms runs, arp or dhcpd storms. But sometimes it is not that obvious and you want to know which traffic flows to your CPU. Time to dump the packets to the CPU. The following has been retrieved from

Acterna Testpad FST2802 Reflector Client

Submitted by cliff on Tue, 20/03/2018 - 15:23

A few years back we had a Acterna Testpad FST2802 (datasheet) on loan from a vendor to test a big rollout of fiber we did together. As we only had one unit we couldn't use it to test other things then the rollout where the vendor had the other unit. So I decided to write a little software program to act as a software based reflector.

Windows Update Delivery Optimization

Submitted by cliff on Tue, 20/03/2018 - 14:20

While troubleshooting a bandwidth issue for a customer today I noticed a lot of TCP traffic between different hosts of the customer on tcp port 7680. As the customer has multiple locations with diverse bandwidths available this started to hog up quite some bandwidth. After some research I found out that tcp port 7680 is used by Windows 10 to distribute windows updates to other domain clients. 

Using BIRD as a route server for BGP analytics

Submitted by cliff on Tue, 13/03/2018 - 10:34

These days there are many public BGP analytics services which all need data to analyze. Ofcourse you could peer directly to it from your BGP routers, but I wanted to seperate it a bit more.

I choose to use bird as a collector for the routes and distribute them to multiple services. As I personally didn't find many examples for BIRD here is mine (privatized a bit here and there)


Reviving a MGE Pulsar Evolution 2200

Submitted by cliff on Mon, 12/03/2018 - 16:06

I recently acquired a used MGE Pulsar Evolution 2200 UPS from work where it was no longer used. It had no working batteries anymore, and there are no replacement battery packs from MGE available anymore. After googling a bit and reading the user manual I found it it is pretty easy to do yourself. There is also a youtube video about the MGE 3000 but it is the same way as with the MGE2200.  You just need the following items: