Network troubleshooting

[Sust]

I live in Philadelphia and have verizon DSL which is connected to my WRT54G(tomato1.28) and has worked great until now.
Interestingly, I have only encountered problems going to yelp.com and that has only recently started since Thursday. Tomato can still ping yelp and I can certainly ping yelp from the Win7 command prompt. However, when I try to goto yelp.com or put in the associated IP address that gets translated, I cannot reach it. This problem holds true for all wired and wireless users of my WRT54G router. I have not made any changes to the tomato router recently and it is damn near unchanged from tomato defaults with no access restrictions set up whatsoever. There are no wireless bandwidth leeches as I have WPA2 setup. Resetting both DSL modem and router separately have not fixed things.

1. How is it possible that I can ping yelp, but cannot reach the website?
2. I suspect something wrong with the router, but what would you suggest as the next troubleshooting steps?
3. Is it possible that yelp has banned my IP address even though I never even post there?

 

[JackMDS]

Every other Internet address works well?

If it does I doubt that it has to do any thing with the Router.

It can be DNS trouble.

Or try this.

WinSock and TCP/IP Refresh.

Type Cmd in the Start Search text box.

Press Ctrl-Shift-Enter keyboard shortcut to run a Command Prompt as an Administrator. Allow elevation.

Type netsh winsock reset in the Command Prompt , and then press the Enter key.

Do the same process for refreshing the TCP/IP just replace the typed command with.

netsh interface ipv4 reset press Enter

netsh interface ipv6 reset press Enter

ipconfig /flushdns press Enter

Restart your Computer.

 

[Sust]

Thanks for the help.
I tried your idea and the problem persists.
Also, I agree that this is likely not a router problem.
I reinstalled the tomato firmware and there was no resolution either.

Dear God... am I going to have to call verizon tech support? :'(

Does someone have a DNS server I can borrow to prove that this is DNS pathology?

 

[drebo]

It's an MTU problem.

Basically, what happens is that your router asks the web server to send smaller packets (usually because the Don't Fragment bit is set) using the ICMP protocol. A poorly configured firewal somewhere between you filters ICMP messages and thus the web server never sends smaller or fragmentable packets. Packets that are too big to fit on a connection but not fragmentable are dropped.

Not being familiar with Tomato, I couldn't tell you where to adjust the settings to correct it, but it should start you on a path. Some MTU value somewhere should likely be raised.

 

[LiuKangBakinPie]

OP

Go to the cmd prompt and enter the following

ipconfig /all

route print

copy and paste both results here

 

[LiuKangBakinPie]

Every other Internet address works well?

If it does I doubt that it has to do any thing with the Router.

It can be DNS trouble.

Or try this.

WinSock and TCP/IP Refresh.

Type Cmd in the Start Search text box.

Press Ctrl-Shift-Enter keyboard shortcut to run a Command Prompt as an Administrator. Allow elevation.

Type netsh winsock reset in the Command Prompt , and then press the Enter key.

Do the same process for refreshing the TCP/IP just replace the typed command with.

netsh interface ipv4 reset press Enter

netsh interface ipv6 reset press Enter

ipconfig /flushdns press Enter

Restart your Computer.

netsh winsock reset
netsh winsock reset catalog
netsh interface ip reset C:\DAF-interface-resetlog.txt
netsh interface reset all
netsh firewall reset

If ping dont work then check your dns

 

[Sust]

Problem is resolved.
Thanks to all who helped troubleshoot, but I simply went to work this morning and now that I am back, the access trouble with yelp is gone. I'm still blaming verizon for all of this 🙂
In retrospect, my wife was also complaining of inability to connect to netflix and download silverlight for chrome yesterday so it seems that it was more than just yelp.
Thanks again to everyone with their suggestions.