RV042 1 to 1 NAT Stopped Working

doppelganger · ‎01-07-2012

Thread title pretty much says it all. I've had 1 to 1 NAT setup for years now with no issues and the other day it simply stopped working. Rebooted everything, had ISP clear arp on their cable modem yet nothing going. As soon as I remove the 1 to 1 NAT on the router the PC has internet access. Add the 1 to 1 back and no out going internet. The configuration is pretty basic and has not changed.

Thinking it could be a hardware issue I swapped it out with another RV042 I have with the exact config, same thing 1 to 1 NATs have no internet access. Upgraded one of the RV042 firmware to Firmware Version: 1.3.13.02-tm, had cable modem replaced, spent numerous calls with ISP. nada

I have found one interesting thing however, any internal machine which is set to dhp works fine, and static ip that does not have a 1 to 1 nat works fine and the last ip in the 1 to 1 nat range works fine. If I extend the range it is always only the last ip that works. Even if I add 1 to 1 nats one line at a time, it is always the last entry that works...

Short of thinking my ISP is out to get me... Any help here would be appreciated!

doppelganger · ‎01-08-2012

Just a little update on this. It appears that 1 to 1 NAT is working only for 1 IP address at a time. Could this be a hardware or firmware issue? As it is happening on either RV042 I use I would tend to doubt it. Is there something that the ISP could have as an issue on their end? Still waiting to hear from anyone that might have experience on this. I have found numerous posts on other forums about 1 to 1 NAT issues with the RV042 routers but have never had problems until now. The cable company isp is trying to be helpful but I do not think I am getting to talk to anyone there that is in higher level support areas.

rocater · ‎01-08-2012

Hello John,

One thing I always like to do is run a trace route from outside the network to the different IPs in the range. This ensure that they are all following the same route back to the router.

It is very strange that it would stop working suddenly. Have there been any other changes in your network recently?

The ultimate test for checking if 1 to 1 NAT is working, would be a packet capture on the WAN side. This would show if the router is translating or not.

doppelganger · ‎01-08-2012

Robert,

Thank you for the response. Yes, an external tracert shows the IPs heading in the right direction and stopping at the router or the ISP hop just before my router. The IPs that have had 1 to 1 NATs set on my router do make it to the router the others to the hope before me, which makes sense as the subnet is shared with others (isp is a cable company). It seems that the router is only supporting 1 IP address on the 1 to 1 NAT. ASame thing for the other RV042 that I have. I've tried setting up the NATs as a range and as individual entries. Not sure what I can do about capturing on the WAN interface but I can ping the public IP from the internal network and the correct machine answers, I can also VNC from the internal network using the public IPs. I suppose both routers could have the same issue that developed at an identical time but that seems rather an extreme. The isp assures me they are routing my IP addresses to me and doing nothing different so I guess I am left looking at the routers as defective and now capable of only NATing 1 and 1 only IP. I sure wish I could see what the heck I am missing.

doppelganger · ‎01-08-2012

Well, I've gone through adding 1 line and 1 line only to the 1 to 1 NAT section and verifed that that IP address worked. I then deleted the entry adn added the next. Each 1 of the 7 IP addresses then work and have Internet access. Once I add a second IP to the 1 to 1 NAT only the highest IP address works. I am going to go bang my head against a wall now.