Virtualizing our Testlabs

The advantages of virtualizing are well known, so I won't go into much detail here. Personally, I have to use a lot of virtualization, especially when studying and testing. Nowadays we can virtualise or emulate anything. In this article I outline a menthod I used to emulate both cisco routers using GNS3, as well as … Continue reading Virtualizing our Testlabs

Source routing concepts

Source routing is basically an option in IP (layer 3) where a packet can instruct a gateway (for example the sonciwall) which hops to send the packet to. Its like the client deciding which route the packets should take. Now this of course is kinda bad because if the client (let’s say he’s a hacker) … Continue reading Source routing concepts

OSPF route failover

A colleague recently asked why, at a basic level, is dynamic routing such as OSPF useful? The very first thing that comes to mind is of course route failover. That is, when a network contains multiple routes to the same network, dynamic routing automatically will "failover" to an alternative route when the primary route is unavailable. … Continue reading OSPF route failover

Controlling routing updates in OSPF

SonicOS 5.6 (still in beta at time of writing) has the ability to tunnel dynamic routing protocols over IPSec tunnels. Similar to the way Cisco does this by tunneling dynamic routing updates through GRE, then in turn tunneling the resulting packets through the IPSec tunnel. In preperation for trying out this new SonicOS feature, I … Continue reading Controlling routing updates in OSPF