Hello,
I recently was sent an NVG589 to replace my NVG510. I always run my modems in IP passthrough mode as I have my own router and I don't need any of the modem's features (wifi, firewall, etc). However with the NVG589, I noticed it blocks all incoming traffic on port 53 with protocol UDP. I need port 53 open as I run my own DNS server. I ran wireshark (a packet sniffer) on my LAN while I sent both UDP and TCP packets to port 53 to my modem's public address (which is forwarded to my router via IP passthrough) from a server outside my home. But only the TCP packets destined to port 53 are allowed through, all UDP packets are dropped which means I can't run my own DNS server. I've verified using other random ports that both TCP and UDP packets are allowed though the modem, only UDP packets on port 53 are dropped. I don't believe this is right (it is certainly not how the older NVG510 works). I feel it is a bug in the firmware and should be fixed.
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I recently was sent an NVG589 to replace my NVG510. I always run my modems in IP passthrough mode as I have my own router and I don't need any of the modem's features (wifi, firewall, etc). However with the NVG589, I noticed it blocks all incoming traffic on port 53 with protocol UDP. I need port 53 open as I run my own DNS server. I ran wireshark (a packet sniffer) on my LAN while I sent both UDP and TCP packets to port 53 to my modem's public address (which is forwarded to my router via IP passthrough) from a server outside my home. But only the TCP packets destined to port 53 are allowed through, all UDP packets are dropped which means I can't run my own DNS server. I've verified using other random ports that both TCP and UDP packets are allowed though the modem, only UDP packets on port 53 are dropped. I don't believe this is right (it is certainly not how the older NVG510 works). I feel it is a bug in the firmware and should be fixed.
For more details: story telling videos