Computer cannot access certain websites...

[BZeto]

I'm working on someones home network. They have 3 computers, one of which cannot access certain websites. nsbank.com is one of them. The other 2 computers on the network have no problems at all. I've disabled the software firewall to make sure it isnt causing the problem. I've tried using both IE7 and Firefox 3, neither can access it. I've ran virus and spyware scans but the most it finds are tracking cookies.

What could be causing the problem? Reloading the OS isn't really an option right now since the computer is used for a home business. Is it possible they had spyware before and it messed up the tcp/ip stack?

Since nsbank.com is an SSL site I thought it might be a problem with SSL but i can access other SSL sites with no issues.

Any ideas would be greatly appreciated.

*I moved this from the Tech Support forum*

Thanks

 

[xSauronx]

sounds like a dns problem. i think in windows the command to clear it is ipconfig /flushdns

 

[spidey07]

What is the error message? This really sounds like spyware - check the hosts file. Also use the command "nslookup" to see what IP addresses are being returned on working computers and the problem one - that can rule out DNS.

It wouldn't hurt to try to repair the stack.

 

[ChAoTiCpInOy]

Check the HOSTS file.

 

[BZeto]

I'll try out all suggestions when i'm back over there this weekend and report back.

Thanks

 

[bobdole369]

MTU? computer has spyware changing DNS to use its own servers? NewDNS?

 

[Tarrant64]

Originally posted by: bobdole369
MTU? computer has spyware changing DNS to use its own servers? NewDNS?

I was thinking this as well but only if that was the only machine on the network and having problems. since there are two others and they work fine I'd just assume they all have the default MTU and that isn't what's causing the issue.

I'm thinking spyware possible. As mentioned above, check hosts file. You can also run Malwarebytes (or spybox, adaware, whatever works for ya) and see if that turns up anything.


You could always try the MTU setting though. If that's doesn't work though just be sure to change it back!

 

[BZeto]

Originally posted by: Tarrant64

Originally posted by: bobdole369
MTU? computer has spyware changing DNS to use its own servers? NewDNS?

You could always try the MTU setting though. If that's doesn't work though just be sure to change it back!

Could explain this and how to do this?

 

[RebateMonger]

If you find the cause, please let us know. In general, I find issues with SSL sites due to security settings in the web browser or to double-NATing (two home routers in series) to be the most common causes. But these causes don't seem to fit your case.

 

[ChAoTiCpInOy]

Try changing the DNS settings (route through openDNS), see how that works.

 

[Tarrant64]

Originally posted by: BZeto

Originally posted by: Tarrant64

Originally posted by: bobdole369
MTU? computer has spyware changing DNS to use its own servers? NewDNS?

You could always try the MTU setting though. If that's doesn't work though just be sure to change it back!

Could explain this and how to do this?

Ahh yes, silly me. Thought I copy pasted some things.

If you open regedit and navigate to:

HLLM\System\ControlSet0001\Services\Tcpip\Parameters\Interfaces\ {.....}

search through the different folders listed there and one will be the NIC you are currently using (should have your current IP and subnet mask, etc. You can add a DWORD value with the value...um I think 1492 (choose decimal value). 1480 might work too.

Restart just to be safe (I usually never have to) and try to access those websites. Worth a shot. If it doesn't work, just delete the MTU key.

 

[BZeto]

Originally posted by: Tarrant64

Originally posted by: BZeto

Originally posted by: Tarrant64

Originally posted by: bobdole369
MTU? computer has spyware changing DNS to use its own servers? NewDNS?

You could always try the MTU setting though. If that's doesn't work though just be sure to change it back!

Could explain this and how to do this?

Ahh yes, silly me. Thought I copy pasted some things.

If you open regedit and navigate to:

HLLM\System\ControlSet0001\Services\Tcpip\Parameters\Interfaces\ {.....}

search through the different folders listed there and one will be the NIC you are currently using (should have your current IP and subnet mask, etc. You can add a DWORD value with the value...um I think 1492 (choose decimal value). 1480 might work too.

Restart just to be safe (I usually never have to) and try to access those websites. Worth a shot. If it doesn't work, just delete the MTU key.

Thanks. Again, I'll give everything a shot this weekend and report back.

 

[BZeto]

Ok it was stupid. Not sure how I overlooked it. They have a static IP on the computer having issues. It's primary dns is pointing to 192.168.1.1 (their router). Nslookups were failing and it wasn't resolving several websites. I changed it to their primary cox dns server and everything is fine.

edit: Although I really thought that their router would just forward any dns requests to cox's dns servers since the router does have them in it's config. Apparently that doesnt work though.