Nighthawk RAX80 and SIP VOIP issues

[voltagejim]

Got a nighthawk router and comcast internet.  We went to a new phone system at work which is based on SIP.  We all use the same exact phone at work which is a Yealink SIP-T46S, and phones work perfectly fine plugged in at work.  When I took mine home last week and hooked it up it worked for a few hours, but then suddenly it stopped working and gave me a "Registration failed" warning on the phone.  Took the phone to the office and plugged it in and worked perfectly fine.

Next day went to work from home again and hooked phone up and didn't even work once this time.  Just that same registration failed message and lights were red on the phone for parking lot and conference and my login.

I went into the nighthawk router settings page and disabled SIP ALG, I verified that the router shows the phone in the devices list, even with the correct model number, and is even assigning it an IP.  I port forwarded the SIP 5060 ports to that IP that the router was giving the phone, restarted the router, restarted the phone, but didn't make any difference, still got the same issue.  I went through every setting I could see in the router and I cannot find anything else that I could change that would indicate SIP would be blocked.

I called Comcast and they said they do not block SIP.  I plugged the phoen directly into the modem cutting the router out completly and the phone worked fine so for sure something with these routers.  Got 2 other coworkers with netgear routers that same thing is happeneing to.  One has a Nighthawk as well.  Everyone else works fine.  

Is there some kind of hidden setting I am not seeing there?  The phone is getting an IP, it just doesn't seem to be able to talk to the SIP server when plugged into the netgear router.

[plemans]

You can try setting the phone with a reserved IP address. After that, setup the phones IP address in the DMZ. 

[voltagejim]

cool, will try that this evening

[voltagejim]

SO I got home with the phone and plugged it into the router and it actually worked for like 30 minutes before suddenyl giving me a "No service" message.  I tried setting the default DMZ server to the IP that the router gave to the phone, but made no difference.

[plemans]

what modem are you using? 

[voltagejim]

Using a Motorola surfboard SB 6141

[plemans]

Are you using IPv4 or IPv6?

[plemans]

I don't know a whole lot about that phone but it looks like its has its own dhcp server built in that can be used/disabled/changed. 

Might be worth checking with Yealink on what setting is best for home use with its dhcp server setup. 

[voltagejim]

using ipv4 at home.

I know we use the FreePBX system at work and we have it setup for DHCP where the phone gets an IP from ur DHCP server at work.

[plemans]

Have you tried it with IPv6?

Also, your work dhcp server might be setup different than a home setup. Might be worth checking with Yealink on it for what their recommendations are for their phone. Especially since its the only thing having issues.