SSH tunnel with PuTTY

Imagine, you can SSH to a host / server and use this SSH server as a proxy to access any local webserver (or anything else) on the local network of the SSH server… This is easily possible with PuTTY (awesome SSH client!).

As a demo, lets say we have the following topology:


We would like to manage the local firewall ( from a pc on the internet. We assume   that we can SSH into the SSH server.

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SDN – A Cisco Champion’s perspective

I’ve had another opportunity to write a blog post for Cisco’s blog site: My second Cisco blog post is about my perspective and view about SDN, Software Defined Networking.

We’ve all heard about SDN but no one does have a real understanding about it. You can read my view on todays SDN in this blog post.

The link: SDN – A Cisco Champion’s perspective

Screen Shot 2015-04-30 at 08.47.47

Configure your multicast WAN for OTV

It is easy to find design and configuration guides about OTV implementations on Nexus 7000 switches, ASR and CSR routers. But it is much harder to find some information about the requirements for your WAN.

Please read my previous blog posts about OTV here, here, here and here. I’ll cover the OTV device configurations in those posts. But for now, lets start with the DCI WAN for OTV.

First of all, there are two OTV deployment options:

  • Unicast mode
  • Multicast mode

The WAN requirements in unicast mode are simple: deliver unicast connectivity between the join interfaces of all OTV edge devices. This is just a simple straight forward configuration, I will not cover this in this blog post.

The multicast deployment is a bit harder to configure and requirements are less easier to find. This blog post will cover the required WAN configuration in a multicast deployment. In this particular scenario, we use dark fiber / DWDM connections as DCI to get a more clear understanding about the requirements and configuration.

First, a drawing to get a view on this deployment scenario:

OTV WAN multicast  layout

OTV WAN multicast layout

This blog will provide you with the most easiest way to get your OTV multicast deployment up and running. There are some more finetune options available, but that will not be covered in this blog.

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Cisco Live Milan 2015


Photo 26-01-15 13 30 14That’s my first word if someone asks me about my trip to Cisco Live Milan 2015 last week. It was my first Cisco Live ever and I really should have been there years and years ago! All those great sessions, a lot of awesome people to have great conversations, meeting a lot of people you know from the community… Cisco Live is the place to be for every Cisco engineer / consultant.

This edition of Cisco Live Europe was in MiCo, Milano. I was really impressed by the size of the event: a lot of people recommend to bring your best walking shoes and I can only confirm this. There are 30 minutes in between sessions and if you’re unlucky, you really need thesPhoto 26-01-15 13 22 33e 30 minutes to find, walk and locate the room of your next session. Another very good impression was the amount of attandees and everything Cisco is doing to make the event as much as comfortable for everyone. You will find Cisco employees on every floor, on every corner to help you with all your questions: where is room x? At what time is lunch? Where is lunch?

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