Web connectivity issues BEF11s4 (maybe DNS?) 1

[ddmiller2]

I have the very wierdest problem. We have four desktops and a laptop connecting through our Motorola SB4220 cable modem. I was surfing the other day, and the Forbes.com site would not come up. The following day I could not access it either. I e-mailed a friend, who verified it was working fine. All other sites I have tried (about a hundred in the last week) work just fine. The same thing happens in Mozilla (latest version), IE (latest version), and Netscape 4.79. This problem occurs on every single computer in the house.

I refreshed the DHCP info in the router setups, thinking perhaps it was a DNS problem. No change.

I jacked my laptop into the phone jack for dialup access (NetZero) and was able to access forbes.com with no trouble.

I bypassed the router and jacked two different computers directly into the cable modem. After refreshing the ipconfigs, I was able to access Forbes.com with no trouble on both with multiple different browsers.

While jacked in to the cable modem directly, I recorded the DNS servers that were assigned. After connecting via the router again, I released/renewed the DHCP information and was assigned the same DNS IP addresses I had when I was connected to the cable modem directly. I still could not access Forbes.com.

In the setup section, I entered the same DNS in the static area. This did not help the problem.

I called a friend who was able to access Forbes.com and had him give me his DNS entries (his ISP=seanet.com). I entered these into the static area of the router setup. I refreshed the IP config on one PC and confirmed the seanet.com DNS were configured on the PC. Still no ability to access Forbes.com.

This happened completely out of the blue. I had not made any changes to the router settings in months and had accessed Forbes.com multiple times since the last access failed.

I have just upgraded the firmware in the router to ver. 1.50 and seen no improvement.

I have active virus protection with up-to-date subscriptions on all computers here and have run multiple virus scans (McAfee & Norton). I have run spyware/malware sniffer programs, too. All turn up negative.

Additionally, I always have a window open to a web mail application. After a period of time that ranges from a couple hours to a couple dozen hours, a click on the "get mail" button hangs the browser. If I ipconfig /release, the browser unhangs. If I open up a different browser (IE instead of Mozilla, for example), I won't be able to get to the underlying web site home page (not just the web mail for the site, but the home page). If I just enter the IP address, it works. This will last for a little while (few minutes to a couple of hours) and then go away.

ipconfig /flushdns does not fix the problem.
There is no problem in the Hosts file.
I have the Windows XP DNS caching turned off.
Flushing the browser page cache does not help.
Flushing the browser cookie cache does not help.

I'm completely stumped. I know this sounds like insanity, but I'm hoping someone here can help me out. I've been working on this in my spare time for about two weeks.

 

[bcastner]

1. If one machine, use the "fix" in my FAQ: faq779-4625

2. If all machines, call your ISP and see if the router and your clients are set to the appropriate MTU value.

3. There are other possible issues. A troubleshooter:

http://www.mvps.org/inetexplorer/answers2.htm#secure_sites

 

[ddmiller2]

Thanks. I'll start working through the suggestions and let you know.

One question before I begin. Most of the items on the troubleshooter relate to IE. While the problem is duplicated there, I use IE only about once a month. Mozilla is the default browser on all machines here. Is it worth going through the IE-specific items?

 

[bcastner]

If your system has mis-registered these DLLs, yes:

regsvr32 urlmon.dll
regsvr32 Shdocvw.dll
regsvr32 Msjava.dll
regsvr32 Actxprxy.dll
regsvr32 Oleaut32.dll
regsvr32 Mshtml.dll
regsvr32 Browseui.dll
regsvr32 Shell32.dll

 

[ddmiller2]

OK. I've gone through the lists, run all the programs, and still have the same problem.

I should reiterate a couple of things:

(1) This problem does NOT exist if I am plugged directly into the cable modem. It only exists when I am plugged into the Linksys "box" in the subject line.

(2) I have no problem accessing any and all SSL-secure sites I have visited

(3) There are three problems I have noticed
(a) Cannot access forbes.com
(b) After a random period of time, access to my web mail (which is not SSL) hangs unless I replace the URL with the IP address. To unhang, I ipconfig /release then ipconfig /renew, and enter in the raw IP address.
(c) About the same time (b) happens, ads from doubleclick's web servers quit showing up.

Again, all of this is resolved when I unplug from my Linksys box and plug directly into my cable modem.

 

[bcastner]

I suspect that a firmware upgrade for the router will resolve your problem.

Particularly if this is a Version 4 of that model router.

http://www.broadbandreports.com/faq/2290

 

[ddmiller2]

It is a version 4.

I updated to the latest version 1.50.10 and no change.
I went back to factory defaults both via the settings via HTTP and by holding the reset button on the back for 30 seconds.

Still no change.

I appreciate you taking the time to help. I know there has to be a solution somewhere.

 

[ddmiller2]

HOLD THE PHONE!

I tried something I ran across on a web search the other day, but made no sense.

I "cloned" my MAC address in the router and all the sudden Forbes.com works.

The reason it made no sense is I know for a fact the MAC address cloning was not enabled at any time since I acquired the router about 8 months ago because I have printouts of every screen in a file in case there is a problem. As I noted, this has only been a problem for about two weeks when it started out of the blue.

Two questions, if you (or anyone else) has a moment:

(1) What's the purpose of MAC cloning?
(2) What would have changed to require this setting to be enabled all the sudden?

I have Comcast service, which I suppose is a partial answer to #2 since they are infamous for making unannounced changes.

Thanks again for all your help.

 

[bcastner]

I did not think Comcast required the cloning. But to answer your questions:

1. You clone the MAC address so that the router "spoofs" the MAC address of the machine used to first setup your cable broadband connection. Many, not all, cable connections require the registration of a principal PC workstation network adapter MAC address when the account is created. This can create issues if you connect a different machine, and certainly creates an issue if you connect a router. Rather than fool around, you "clone" the MAC address of the original PC so that to the cable system the router appears as the original device. There is nothing illegal or "hacker" like intended by the process. It simplifies your life for cable systems using MAC authentication to clone the PC MAC so that the router's MAC appears the same.

Early on, the intention was to restrict the use of the cable internet service to a single device. If your cable system insists on this is your EULA (I do not believe Comcast does anymore) then change providers.

2. Some cable systems require that the device identify itself in a specific way. The router as a host device will require a Host name, and the authentication entries must be exact. Usually this is your username@comcast.net, with (case sensitive) your password. Check the router setup page to make sure this was done exactly right.

3. There might be an MTU issue. The only way to know is to test it. Use the BroadBandreports site to test your connection, and their freeware DrTCP tool to adjust your client settings:

http://www.dslreports.com/tweaks

 

[ddmiller2]

Thanks so much for all the help. FYI, the problem is rampant on Comcast's own message boards.

I did the MTU thing, we're both set at 1500.

Funny thing is it is spoofing the MAC of my new machine, postdating the installation of the router (and predating the problem by about four months).

I'll hang on to that idea of the original machine name, though. Comcast said it was no longer necessary after the first system update after the @Home/AT&T nonsense, but who knows. I still have what it was and the next time it goes batty I'll give it a shot.

Thanks,

David

 

[bcastner]

Read and stay current on the best Linsksys site on the web:

http://www.broadbandreports.com/forum/equip,16