Simon PainterSomewhere to keep things
There used to be a great little website for route summarisation and it did it far more intelligently than Cisco kit does it. It looks like the site has dropped off the internet which is a shame but there is a handy python library called netaddr with has the same capabilities. I have written a […]
I am working on a project that involves moving a router from one BGP ASN to another. The topology above shows the current situation and we want to move R2 to ASN20 and have it hooked up to R4 instead of R3. Normally this would be pretty trivial however the owner of R1 in ASN […]
Some of my posts are just things that I was pretty sure worked but wasn’t 100% on how it worked and what the exact config looked like. In these situations if I can’t find something in a blog or on the Cisco site I post something to make it easier for the next guy trying […]
I found a very clever site that does route summarisation from a list. This is ideal if you dump out a copy of your routing table and want to see where the routes can be summarised. It’s also useful if you have subnets for a firewall rule that you want to consolidate. http://www.netmatics.net/FreeTools/IPv4SupernetTools/SupernetCalc
This is the list I use of looking glass servers with web interfaces. It makes internet routing diagnostics a lot easier. http://www.bgp4.as/looking-glasses There are also a couple of looking glass routers you can telnet in to such as this Global Crossing (Level 3) one. telnet route-server.gblx.net
In this scenario we have a dual connected site and are using BGP multipath to load balance the traffic over the two connections. This is very dangerous to do when beancounters are around because they often want you to use both connections to 100% (or at least over 50%) so you end up without the […]