New Job, Updated blog

After eight years working at Wavex I have taken the decision to move on for a new career challenge and I am now a Senior Infrastructure Engineer at IT Lab. The past eight years have been a very good learning experience and I have developed from a young and inexperienced Service Desk Engineer into a more confident and technical IT Professional with the ability to communicate on a technical and commercial level to explain the problem and solution in a given situation.

As part of this change I have decided to try and remove some of the more juvenile aspects of my website and tidy up some of the blog posts that were written before I started my professional career as I realised that many of these were inappropriate content for a modern audience. All the blog content has moved from the subfolder “blog” to the root of my website and I am hoping that as my new role develops that there will be new content added over the coming months to read.

Thank you to all those at Wavex for their time in the past and here’s to the future.

Matt

Using OSPF to maintain site-site VPN across multiple WAN links

Having a Single Point of Failure (SPoF) on your network is never a desirable situation and recently I implemented a multi-site set-up where each site had two internet connections and there was a requirement to enable the satellite office to connect to the head office at all times. Each site has a Juniper SSG5-SB firewall as well as a 10Mbit leased line primary Internet circuit and an ADSL backup.

With the Juniper SSG firewalls it is possible to use Policy Based VPNs to maintain multiple tunnels and have the firewalls switch between these as required however you end up with four policies on each firewall and you cannot tell from looking at a routing table where the traffic is flowing. In this instance I decided to make use of OSPF to dynamically route the traffic depending on the availability of the VPNs at each site.

The first thing we need to do in order to implement this is to put each Internet connection into its own Virtual Router so they can run independently of each other.I have covered this in a recent blog post which you can read here.

Once you have the two firewalls setup with each Internet connection in its own virtual router we need to setup the VPNs. This is done with a new Zone in the trust-vr and we will need four numbered tunnel interfaces on each firewall.

On the second site firewall you will need to repeat the commands but using the other IP address in the /30 in each case.

Now we need to setup the VPN tunnels. You may want to change these based upon your requirements however I have used these settings regularly and they work well. NB you will need to apply similar settings on the Site-B firewall with the various endpoint addresses for SiteA

From the GUI you should be able to check that these have come up by going to VPN -> Monitor Status.

We now need to enable OSPF on the trust-vr and configure the interfaces to communicate using OSPF. This should be completed on both the primary and secondary site firewalls.

You can check the OSPF status by running the following command

Finally we need to setup policies to allow traffic to flow across the VPN between the two sites.

To test this you need to take down the Internet connections one by one and watch the routing table update on each firewall.
You should now see all four IPSec VPN Tunnels show as active and the route between sites will be via the Layer-3 tunnel interface for the relevant tunnel.

Hello world!

UPDATE 29/12: The content should all be mirrored across from the old blog to the new site. I am working on a URL rewrite for the old hyperlinks from search engines etc to link to the new blog but it looks to be up to date.

Hello, and welcome back to my blog. Over the years this site has been in a state of disarray and lack of updates so I have decided that an overhaul is needed to get this back on track. All the old additional content from my University days has been consigned to the Internet dustbin and the site is just going to be a location for me to blog about technology and things that interest me.

I am working on reimporting all the old content from the old database and making sure that the images are all touched up and reimported so if you are looking for an old article these should be back in the coming weeks.

Thanks,

Matt