After a bit of a kerfuffle getting my 2Degrees Home Phone Plus working with my SPA112 on my UFB connection (read my other posts if you are interested, but I'm not sure it is pertinent to this question..and thus a new post).

However, I have noticed some unusual behaviour.  It seems that the re-registration windows is only 30 seconds regardless of how I have my SPA112 configured? 

I have my SPA112 configured with a 3600 second registration interval, but no matter what happens it looks like it expires and registers every 30 seconds.  I'm not having any problems staying connected or making/receiving calls.

I have another SIP provider for the USA (localphone.com) and if I leave my 2Degrees configuration identical and only change the server name and the userid/password, my SPA112 will connect to localphone and it honors the registration expiration time I have set in the configuration.

Is 2Degrees able to enforce a shorter registration windows from the server side and do they have it intentionally set to 30 seconds? If so, that is fine.  I just want to make sure my equipment is behaving and not spamming their server and is doing what it is supposed to do.

I'm using most of the information/configuration details that @sbiddle has previously provided - they are quite old now, but still seem to be relevant and useful.