Router Problems.....


Active Member
A couple of days ago I got the Comcast Digital TV service installed. I have had internet through comcast for years and never had an issue. The reason I mention the tv install is because for the first time I have installed a splitter on the wire coming into the house.

So this is what is happening. I think it is more of a router issue.
If I connect the computer directly to the modem it works fine...the problem happens the minute I add the router to the equation. the IP fields etc were all zeros. I reset the router and it started working. A couple of times the unplug the router and the modem routine worked but now it only works if I reset the router.
Every couple of hours the internet connection dies and I cannot get internet on any of the PCs. The other check is that my VOIP phone stops working. The VOIP box is connected directly to the router and the PCs are connected to a switch.

Please advise as this is causing major headache.

What could be causing this????

You need to power cycle the modem (although it sounds like you do that). I forget the specific reason, but because the mac addresses are different (or something like that) it needs to be cycled.

Usually then it works. It sounds like you have something else though.
I have had this issue for several months as well. Comcast did all kinds of testing only to say they could not find anything wrong. They did however replace my cable from the pedestal outside to the house and I have not had hardly any failures since. The only thing about my setup that they did not like was that I had 2 splitters between the feed into the house and the cable modem, they dont like to see anymore than one.

How many splitters, and how many TV locations do you have connected? Also make sure the cable modem is on a split by itself.

Wire from outside split once and it goes to the modem the other goes to the TV.

The service works fine when a PC or the VOIP box is directly is only when I add the router that is works and then dies in a bit. Once it is dead If I just unplug the rj45 cable fromt he router and hook it to the pc it works fine.

PCs are all over the house and I do need a router in the setup. This is s annoying.

Sounds to me like a bad router. Can you give the make/model? You might see if there is a firmware update available. This might resolve your issues.

Also, when the connection is lost can you connect to the router via your browser? will it return a ping? You need to figure out if the router is down or if the connection between the router and the modem is the problem. Your router "status" page will shed some light on this aspect if the router's web server is working.

also, has lots of info for figuring out router problems.
If you've only used one PC on the modem, it may indeed be looking for the MAC of the PC for authenticaiton. Bellsouth does (did) this with their DSL service, and if the MAC in use was not registered, it would die in about 2 hours or on the next DHCP update.

Most routers allow you to change the MAC on the Inet interface. Try putting the same MAC that's on the PC into the router and see if it works any better.
so you have -

demarc -> splitter -> modem -> router -> switch -> computers?

if that is the case, make sure DHCP is disabled on the router so the modem can assign the IP addy from its pre-set range. sounds like there is a conflict ... if the modem assigns an IP from its range, say 192.168.1.XXX then the router assigns the computers an IP from the 192.168.0.XXX you have now created two independent networks inside your house.

after verifying that, turn on your TV, and call your cell phone, then do a bandwidth test to make sure that you have enough throughput. if you dont, have Comcast / Time Warner replace your dated RG59 with decent quality RG6.

if neither of these work, you may have a damaged line inside the house ...
Thanks for all the is IP conflict. I think I have fixed it as the phone was working this morning.

All the wiring is RG6. I just have to do a broadband test now to see if I have the right speed. I guess Comcast won't do anything if I tell them the speed is low.
Ok so the router issue is not really resolved.

This is what I did:
All the devices I have connected are assigned an IP address range is the default. However I entered the IP addresses so that they would not change and also did the mac address. The range is onwards.
So my ELK is and it is coded as such in the setup so if I change the port or switch off the router it should pcik up

The problem is that my notebook computer is setup the same way. So I noticed that once I unplug the notebook and plug it in another outlet in a different part of the house the router seems to go bonkers. I have to go through the motion of setting up everything again or it won't work. I know Comcast is fine as if connected directly to the modem the laptop alsways works fine.

Please advise as the laptop is carried around. My wireless router broke so that option is out for the time being.

If you are assigning IP addresses that are still within the range of the DHCP server in the router, you will continue to have problems. is usually the router itself, internal interface (on your network). This is what you use for the Gateway item in your static IP configuration. In many cases the router will also proxy DNS, so you'd use it as the DNS entry in your static IP config, too.

Check the address of the router's Inet port, as it gets it from the modem/cable. It should not be in the same network space as your internal IP addresses. (192.168.0.x)

You can use DHCP AND statically-assigned IPs, just make sure the statically-assigned IP addresses are outside the DHCP range (which I think it usually something like to .100). And you have to configure everything in your statically assigned devices - IP, mask, gateway, DNS. is the default gateway....if I set the range for the dhcp server starting at onwards. Then how would I setup the notebook to lets say

Will the router see the notebook connected as it won't be in the range of the DHCP server?

The router will see everything in the range of 192.168.0.x

You are just saying 'assign dynamic addresses to anyone who asks starting at

For anyone who has a static address (like you just set it on the laptop under network properties for IP, to use a static address (and the other settings that go along with that, subnet will be
Gotcha..what about device that do not have the ability to set the IP example the VOIP router. I assigned a fixed IP in the router setup as I have no idea how to assign a fixed IP for the VOIP router.

Thanks & Regards,
Then it probably defaults to DHCP. Check the manual, sometimes it has a default IP and you can login and change the settings.

Hmm, wait, you have two routers? A main one and a voip one? If it is a router, you should be able to log in and set the ip, just like in the other one.

Maybe you should post model numbers so we can understand better what you are dealing with.
Sounds like what you were doing by "setting" the IPs in the router was specifying that the DHCP server should reserve the IP for the specific device (DHCP Reservations). For all static IPs, you would set them on the device itself, such as the laptop, not a router, but reserving should have worked ok, too.

Did any of your computers show the "IP address conflict" error message?