I have a similar issue... I'm using ameritech ADSL (their service until the last few weeks has been horrible, frequent outages, sometimes for days), and I have a static IP so I can host web sites. I use worldwidedns.net as my DNS service for my sites and they list 2 name servers. When I enter those IP's in my DHCP server, I loose name resolution from all the DHCP clients on my network. I use the name servers that ameritech plugs in during authentication and everything works (it's PPPoE authentication, essentially my gateway - SME - is a DHCP client but it always issues my static IP).
This leads to a couple questions:
What would be the advantage of a service provider blocking outgoing DNS requests, those destined to name servers outside the ameritech network?
The other question is not really related, but how can I see what my connection stats are? I don't subscribe to the Mitel services but I do use SME Server as my gateway. I want to be able to track internet outages - when my connection goes down and for how long. I don't know if I've been able to stay connected 24/7 for the last week and a half, if I have, it's a new record (I put SME online a week ago last Sunday). Outages have normally begun late in the evening and extended into the morning hours. Prior to using SME, I used WinNT with WinRoute and their Enternet client. A reconnect required manual intervention, I'm guessing SME will reconnect when service is restored. I've checked logs from the administration interface but I don't see anything specific to connectivity (unless it's normally there and I haven't experienced any outages).