I just installed my new DIR-601 and I'm unable to make phone calls with my VOIP device. The device worked just fine with my previous wireless routers. I verified that the VOIP device itself is not a problem by directly connecting to the DSL modem. So, it is certainly my D-Link router which is the culprit.
I tried disabling SIP ALG in firewall settings. I also tried disabling SPI. None of them helped. Anybody else with similar problems?