Category Archives: Network

Monitoring network traffic: pmacct and Graphite

Recently at work we’ve needed to gain visibility on traffic flows across a global MPLS cloud. I would have explored open source solutions anyway but we didn’t have any budget so I was pushed that way regardless. The first part of the puzzle came in the form of pmacct, a daemon that uses pcap to […]

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Great NANOG presentations

I was reminded by @dritans tweet that there a lot of great NANOG presentations which tend to get buried amongst the archives. The particular one he linked to is A Practical Guide to (Correctly) Troubleshooting with Traceroute [222KB PDF] by Richard A Steenbergen. This is a terrific primer for those who have never dug deep […]

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Running RANCID on top of BZR and with multihop

Long time, no write. Been busy moving countries, as you do. Started a new job too. Been setting up RANCID and wanted to pull together all the pieces here: RANCID Let’s start in the obvious place, www.shrubbery.net/rancid/. I prefer my own, slightly different, expansion of the acronym. Really Awesome Network¬† ConfIg Differ. If you are […]

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If fibre goes down in a forest, does the twisted pair hear it scream?

So at $work[0] we’re trying to bring up a new service for a customer. It’s a 2meg service from T, which terminates on our side like so: fibre -> managed media converter -> twisted pair -> router We think we’re ready to turn it up and a T technician is booked. For 01:30am due to […]

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It must be a bad day to be in the hosting business…

Dreamhost – “Due to a typing error on our primary router while trying to block a denial of service attack, DreamHost is currently offline.” Out of band access anyone? Nearly Free Speech – It will probably have changed shortly but right now it reads “Our master MySQL server has blown more drives, and this is […]

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Many to one SNAT on Cisco IOS

So, at $work[0] we needed to do a “many to one” SNAT on Cisco IOS. I’d only ever previously done this by SNAT’ing to an interface, however this required specifying the IP. My Google-fu failed me, I could turn up how to do the “SNAT to interface” and “SNAT one to one from a network […]

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