Comcast setup problem, multiple PCs

I just switched from Verizon's DSL to Comcast's cable internet. I bought Linksys WRT310N (since Comcast is too greedy/cheap to include with their modem like Verizon does) to connect 3 computers and all the other wireless electronics. Now before switching there was no loading problems, but after switching Facebook wall links and all apps start coming up as "Invalid URL" a couple XML errors and even Flash has more trouble than usual. This will happen on all 3 PCs, usually it starts with one and then they all will encounter it. It's across 4 different browsers instantly on my PC alone, so it isn't their setup. It seems my IP gets blocked for some amounts of time and then it's fine again. I've tried releasing and renewing the IP via ipconfig and that will usually solve the problem for a short time. I can't ask Facebook or Comcast, they will only blame the each other and would be no help at all. So it's a problem between Comcast, the router default setup and Facebook with the difference of how Verizon handles IPs from Comcast being the probable answer.

Consider flushing the Domain Name Service cache on each machine in your network.

Click Start - Run - (type)CMD - (press)enter key
Copy/Paste: ipconfig /flushdns
If you are typing this in, note the space between the g /f
It needs to be there.


Now lets check some settings on your system.
Enter your Control Panel and double-click on Network Connections

Then right click on your Default Connection
Usually Local Area Connection for Cable and DSL
Left click on Properties
Double-Click on the Internet Protocol (TCP/IP) item
Select the radio dial that says Obtain DNS Servers Automatically
Note: Do this for all Network Connections
Press OK twice to get out of the properties screen and reboot if it asks

Thanks will try the flush command and report back later if it helped. (shouldn't take long, the problem is pretty common) For the network config, it was already set to obtain automatically. I did read something about cloning DNS and they mentioned a setting in routers, didn't see that one in mine. UPDATE: It's still getting the invalid URLs and XML problems.

Kyllinge, first you need to plug directly into the Comcast modem and see if the problem persists.

The other possibility is that the comcast modem is dishing out the same network address as the router is dishing out to your local computers causing a routing problem.

Please identify which comcast modem you have, and if you have a phone service on this unit also.

If the problems do not occur when plugged directly into the Comcast modem, then while you are still plugged into the comcast modem, please go to a command prompt on the computer (start -> run -> CMD -> Enter) and type ipconfig and press ENTER. Please tell us what IP address you are receiving for your local area connection.

Then we can look at changing the router configuration.

No, the problems only exist when the connection is run through a router and split between computers. I do get phone service from them, think there's a splitter from the wall with one to the modem and the other to my phone. the Modem is an "Arris Touchstone TM722" IP Address. . . . . . . . . . . . : Removed from general viewing

Ok. This is a different device than what Comcast uses in our neck of the woods, but there is a problem with the ones they use around here that may also effect yours. On the devices that have phone service, they do not take well to changing what computer/device is plugged into them. They must be powered down completely, which includes removing the battery back up that is in them. Then you can power them on and plug in the device you intend to use on it. Its possible, that the problem is changing between the router and other computers and not resetting the modem first. So, lets try that before digging in and causing more headaches than we need to. Go ahead and power down the linksys and the modem (remove the battery also). Connect the ethernet cable between the Linksys and the modem again. Next, plug in the battery and power to the cable modem. Wait about 60 seconds for it to initialize. Next, plug in the power to the Linksys router. Wait about 60 seconds for it to initialize. Now, go ahead and use your other computers and see how they work. If you continue to have problems there is much more we can try, I just want to knock out the simplest of those first. Let me also clarify that you are NOT using ethernet AND USB out of the cable modem correct? They do not work together. All computers should be plugged into the linksys router, and nothing should be plugged into the USB port on the cable modem.

No, not using both. This model doesn't even have a USB port. Hopefully the battery isn't too hidden inside the modem. Digging around the insides of a PC is one thing, I know how to put them back together and know when something is in wrong. I do know it does keep power when the power cord is removed, just assumed it drew power from the phone line. Never cracked one of these open before… well, I did see insides to a DSL'd modem but that happens now and then when it's thrown into a wall… Anyway, I'll look inside tonight when others are asleep.

Hi.

THere isn't anything to crack open. The battery is a user serviceable part. There should be a cover on the end of it that you pop off and pull the battery out. It shouldn't have any screws or anything.

See here, it will show you how: http://www.arrisi.com/support/guides/_docs…uide_Std2-1.pdf

Ok, I see it now. It just isn't as obvious as they normally are. I did notice during the ipconfig when hooked up to only the modem that the subnet mask is different than when it's hooked to the router. Would that be a problem? It doesn't assign the usual 255.255.255.0 I'm usually good with troubleshooting computers, except when it comes to networking.

No, the ip information is normal. The modem is assigning a public IP address, and that is what we want. The public IP address has a different subnet and is dependent on what Comcast has allocated for that area. Let me know if you continue to have problems after the power cycle on the modem.

I did the power cycle and removed battery etc. Still getting invalid URLs. I did find another example of where I get the invalids. I got the problem just coming to this forum to report I'm still getting them. The main page was fine, it was coming to the forum itself it wouldn't allow. I had to release/renew just to get back in.

Are all the computers you are having this problem on wireless?

No. Mine is wired and the other 2 are wireless. My wireless devices don't seem to have any problems. (Wii, Xbox, Netflix)

Ok. Lets try to start fresh with this router.

Look on the bottom of the router and identify what hardware version you have. Either 1 or 2. You'll need to know this to upgrade the firmware. It should be near the model number (WRT310N) and it might say HW VER, or V1 or V2, etc.

Next, lets disconnect all wireless devices and computers from the router by shutting them down. The only computer to leave on will be the one that is hard wired to it.

Now, lets perform a hard reset on the router. Look on the back of the router where the cables plug in. Identify a recessed button that says reset. Press and hold that button for more than 10 seconds, then release it. This will wipe out any configuration and restore the router to factory defaults.

Once this is done, you should be able to get on the internet with your hardwired computer. It may take a minute for everything to reset and start working again.

Now, lets download the newest firmware for your router from here: http://homesupport.cisco.com/en-us/wireless/lbc/WRT310N Click the download section and make sure you select the right hardware version. Download the firmware file, and save it to your desktop.

Next, click this link: http://192.168.1.1 A new browser window will open and you will be prompted for a username and password. Enter 'admin' and 'admin' for user name and password. Your router's configuration screen will come up. Click "Administration" and then click the "Firmware Upgrade" sub heading. Next, click the "Browse" button and find the firmware file you downloaded on your desktop. Once chosen, click "Start The Upgrade" to commence upgrading your router's firmware. DO NOT interrupt this procedure. When the firmware upgrade is complete the router will reboot and you may or may not be returned to the screen you were on. Go ahead and close the browser window and re-open your router's configuration by clicking the link I provided above. Login with the name and password again if necessary.

Now, click the "Wireless" button. You should be under the Basic Wireless Settings sub-heading. In the basic settings, for "Configuration View," choose MANUAL. Next, enter the Network Name (SSID) that you want to use - Note: Make this different than what you were using. This is what will be displayed when you search for available wireless networks in order to identify YOUR network. Other people that are close enough, will see this name. For Channel width, select AUTO. For Channel, select 1. Click Save Settings.

When the screen re-appears choose the "Wireless Security" sub-heading. For Security Mode, choose WPA2 Personal. For Passphrase, enter a short password/passphrase that you want to use in order to connect to your network. This passphrase will be required in order to connect to your wireless network, and will be required to be typed into each wireless device the first time you connect. Click Save Settings.

All other settings should be left at defaults.

Re-connect all your wireless devices, by locating your wireless SSID that you entered previously, and enter the new passphrase you provided to connect.

Test out your internet connection and see if you still have any trouble.

Nope, didn't help at all. I didn't think it would as none of that would explain why my one wired computer getting the invalids too. It's mainly web sites. My other stuff has no trouble, and the MMO I play isn't affected either.