Comcast Xfinity DPC3939 Wireless Voice Gateway for Triple Play......

[88keys]

Okay, so a friend of mine had to get this router for Comcast's Triple Play service and before I proceed further I want to know if these things are just pieces of sh*t or whether it's just this one in particular.

First of all this thing takes a horrendous amount of time to boot. I've never seen anything this bad, his PC boots faster. It wouldn't pick up a WAN ip so I couldn't even get to the the walled garden to activate it so I ended up calling Comcast to do so. After setting it up, I noticed how slow it was to change settings and navigate the firmware. It was just atrocious, routers weren't this slow 15 years ago.
Anyway, got all his port forward settings and stuff situated and working, but then I ran into a road block. I have one instance in which I need to externally forward a port and couldn't get it to work. Tried, alternate ports, turning off firewall, DMZ, and nothing worked.... After awhile of frustration, I looked into parental controls and noticed that its set to block everything by default. In there you have to enable services and I tried doing that an toggling other various settings and got nowhere and gave up.
At this point I unlplugged it to move it back where it belongs and low and behold, it wouldn't pick up a WAN IP address. So I hooked up the old modem/router and it just worked as expected so I'm pretty much convinced that this thing isn't working properly.


Got home and did a little bit of reading about this and apparently the only way to work around the port forwarding issue is to put it in bridge mode which means that he would need to buy a router because his other device is a modem/router combo. That being said I have to figure out somethings so he knows what his options are.

I just can't imagine a device performing that poorly without being defective, so I advised him to return it for a replacement. However, he needs to use a Triple Play sanctioned device which can only be acquired via comcast to take advantage of the $70/month savings. Without having one, Comcast was charging him the extra money automatically because he wasn't using a Triple Play device and he would have to call for them to remove the charges.
FWIW all Triple Play devices are

So here are my questions.

If DPC3939 really is that bad, does he have any other options available via Comcast that could perform better and/or solve his port forwarding issue.

Is it possible that just renting this device without using it could solve the billing issue? Seems like the simplest solution here.

If the above is not the case, then could plugging it in and hooking it up to coax (so the data center would see the device as connected) be enough to solve the billing issue?

Thanks in advance.

 

[88keys]

http://forums.xfinity.com/t5/Your-H...ot-working-on-DPC3939-What-gives/td-p/2290579

Here is a thread I just found on similar issues with the device. Might be helpful.

 

[88keys]

So, Comcast came over and replaced his Router/Modem with a new one and it picks up a WAN IP as it should, but it is still slow, but not as bad as what I was dealing with before. I was able to open the ports via Port Forwarding, but also had to enable the device as a Trusted Device via parental controls which seems kind of redundant. It also has no NAT loopback which I thought of as being a pretty standard feature but I guess that's not the case. Furthermore there is no AP isolation feature available for Guest Wifi which isn't that big of a deal, but I would honestly rather have that than have two services managing my NAT firewall, but whatever.


Now that it's all setup and working, I can say that this isn't a horrible router, but if it were mine, I would put this thing in bridge mode and use my own router.

 

[C2bcool]

From experience all the combo (modem/wifi) Xfinity/comcast units suck. Its a multitasker (jack of all trades if you will), so its going to be bad at something because you can only put so much power through the unit.

That something it is bad at is WiFi. I have had both triple pay and double play and regardless I have bought a modem and router (Arris TG722 EMTA/modem and ASUS 68R - still running at my parents for triple play). Originally they had a combo unit that had horrible speeds and even worse wifi. Now they get 100-120Mbits hard wired and about 80-100 through wifi in most areas. Even in the farthest reaches of the house it never goes below 50.

Now I use a rented Arris TG1682G 24x8 modem/wifi at my house (will buy my own modem when DOCSIS 3.1 modem prices come down a bit and have more options). Well the Arris TG1682G has HORRIBLE wifi (great modem though) and you can see the bars drop a few feet away and was basically unusable upstairs. I also live in an old 2-story thick walled home. Well I put the Arris into bridge and now have a TP-Link AC3000 wifi router and I get just above my advertised speed 25mbits (getting 28) everywhere via wifi in my house.

Basically, put the rented unit in the bridge mode (or buy your own modem/emta that is Xifinity approved) and purchase a wifi router and NEVER use a combo unit for wifi again.

 

[QuietDad]

As a sub contractor for Comcast and Cablevision and using both services in different houses, I have in all cases bought my own SB6183 or SB6190 to get internet and telephone and connected it to my own wireless routers. Saves me from becoming a hotspot for the ISP and neither company does wireless well except for their public hotspot that you cant use anyway without configuration work