Well I tried FireFox and to my utter amazement it worked. I signed in and no more requests every time I click a link. This is bizarre for a number of reasons:-

- Safari is usually at least as well behaved as FireFox. I still keep FireFox just in case, but nowadays it is normally Safari that works better.

- I have used Safari to configure the Vigor 2820 router since day one and it has NEVER had a problem. So why does the 2820 IPPBX throw a wobbler when I use Safari? I hate to say it, but this has to be down to Draytek's crap programming.

So, I've configured the trunk OK, but it cannot register. However, is this due to both WAN interfaces being disabled? I tried it with Auto and also LAN/VPN, but it made no difference. Does it HAVE to have a STUN server? Is it possible for the IPPBX to register to a SIP server via the LAN interface?

Just to update the Safari problem.

I've been using Firefox until now and that's been working ok, although regular complaints about an invalid prompt kept appearing. However, since upgrading the firmware from 3.5.6 to 3.5.7.1, I now find that Safari works perfectly which indicates the problem was within the Vigor rather than Safari being at fault.

I've only managed to get SIP registration through one of the WAN ports.

Well I have eight of these running across various clients and have never experienced the problems above. Not to say the 2820IPPBX isn't without it's faults, some of which still need serious work, but I configure them with a Mac (and Firefox) and have some registering SIP on WAN1 (ADSL) and WAN2 (Ethernet). Note, you need to choose this both in the account setup page and in your dial plan.
I use voip.co.uk for all my connections and getting these routers set up and registered is usually a 10 minute job.. (minus setting up all the phone extensions and dial plans of course) if you can't get registration you can either discuss what login attempts your router is making and whether your SIP account is set up to be compatible at the SIP providers end (sometimes their end needs to be reconfigured to work with the draytek, a 5 minute job usually) and finally you could telnet to the router to see what it is doing and why it's failing. That last bit assumes you are trained on the IPPBX and better still have AVP status with Draytek.