I’ve just plugged in my new 2820 and have a strange issue: I’ve got a Linksys ATA (SPA1001 at the moment) and it won’t register. It worked fine on my previous 2900VG but not on this one. I’ve tried a brand new SPA2102 and it won’t register either but I have a direct SIP trunk on my phone system to the same provider and it has registered OK. I’ve not changed anything from factory default yet apart from the ISP details to get connected.

 

Solution:

Put the primary and secondary DNS addresses of the ISP into the Internal SIP device.