I have recently installed Splunk and have a spent a bit of time getting it to work with Cisco IOS devices. So here is a post of a few things I have found that may be useful to first-time Splunkers or just help make it a bit more useful.
The plan for Splunk for me is to monitor faults, track ongoing performance issues and for managing inventory. Note I have only configured this on ISR routers and switches, I haven’t tried it on any ASAs, voice gateways, servers or WLC/APs. Continue reading
I was recently working on some equipment for a client and had to enable SSH without having a domain defined.
Is it possible? Short answer is yes and there are a couple of ways of doing it. Continue reading
The other day I finally got around to writing a script to automatically deploy config to a bunch of devices. Finally! I have been planning on doing this for a number of years (I think eight years since I originally said I would). It just turned out that every time I kinda/sorta/maybe needed it over the last decade or so, it turned out that I could do it manually for just a little bit less effort.
Those days have a last come to an end.
Useful command of the week: next-hop-self.
Today we are going to configure an OSPF Virtual Link.
What is it?
Before we answer what it is, take a step back and look at one of the basic requirements of OSPF. That is, all areas must be connected to the backbone area (area 0). A virtual link gives us a way around that requirement.
If for some reason, you are stuck with a topology where you must connect a non-zero area via another non-zero area you can create a virtual link between the ABR in non-connected area to a router in area 0. That will hopefully make a bit more sense in a few minutes.
This is a pretty common scenario. You are running and IGP (in this case, OSPF) on your local network and you connect to another company or ISP via an eBGP link.
Your goal is to leak some of the external routes received via BGP into your IGP, and in turn leak some of your internal routes out via BGP. The constraint is you don’t want everything. Only the routes you decide.
This post is about extending your OSPF routing domain through a VRF in a MPLS backbone. If you are unfamiliar with the MPLS side of things check the previous post out. This post only focuses on the PE/CE side of things, it assumes that a working MPLS backbone has been set up.
Then you have the choice of if you plan on using the MPLS link as a primary link or as a backup.
Here is a step by step example of how to set up a very simple MPLS-VPN. Like last time I am doing this entirely in GNS3 using 2691s running 12.4(25d).
So the point of this post is to define a per-flow explicit path. Rather than just routing it one way or another using MPLS-TE, route some traffic one way and some another using some Policy Based Routing.
Here is a step by step configuration example to configure a specific path using MPLS-TE tunnels.
This was originally going to be a post about MPLS Fast Reroute. However two things happened, one the post became excessively long and two, I realised none of my simulated routers support MPLS FRR. Also, the Cisco Feature Navigator is lying to me again (FRR is supported on a 6500, FN claims this isn’t so.)