Contact address fixing in OpenSIPS

As a retirement/lockdown project, I have written a series of articles exploring when and how you should fix the address values sent in some SIP headers. These articles will be ideal for beginners to use as a tutorial explaining some of the tricky basics of the SIP protocol, but also for more experienced VoIP solution designers who want to understand how OpenSIPS handles tricky problems with NAT and how it conforms to International SIP standards.

They say it’s good to learn something new as an antidote to lockdown blues, so I hope these articles will give your brain a good workout:

Record-Route and Loose Routing

I have just published a new post on my wiki site which examines how Contact, Record-Route and Route headers are used in what is known as “loose routing”. This is a somewhat fundamental part of understanding how SIP Proxies work and if you don’t get this, then you’ll probably find it very difficult to understand what’s going on in a SIP trace or packet capture. So if you don’t already have this topic under your belt, go and take a look at my latest tutorial article. Just click on this link:

Contact and Record-Route headers explained

…and, if you find it helpful, please remember to use the Like or Recommended buttons that you’ll find at the end and start of the post.