We recently swapped our router from a Netgear DG834G to a DrayTek Vigor 2710n. The DG834G never caused a problem but with the 2710n, 3CX generates the message "Connection error Timeout while contacting DNS servers for _sip._udp.sipgate.co.uk". As far as I can see, the correct ports are open and forwarded and the 3CX firewall checker backs this up suggesting that all tests are passed. Swap back to the DG834G and the problem is resolved with the connection registering almost instantaneously. Are there any special protocols for SipGate that may be causing the problem? Some extra information that might help in diagnosing the problem: 1. When the router is swapped from the DG834G to the Vigor 2710n, there is a short period of time (perhaps up to 30 minutes although I have not timed it precisely) where the registration of 3CX with SipGate remains intact. After that, the registration drops and it is not possible to reactivate the registration without swapping the router back to the DG834G. 2. If I change the SIP server setting from sipgate.co.uk to your IP 22.214.171.124, 3CX registers with SipGate and it is possible to make outbound calls but inbound calls are not routed through to our 3CX server. Instead the SipGate voicemail is activated. We really do want to continue using the DrayTek router so any ideas that you might have would be most welcome!