Routers and VPNs

[Jeremiah]

Hi Guys, I'm having a wee bit of bother.

I previously had a VPN set up to my Uni's filespace on my home desktop. I wanted to remove the VPN, but some really weird things have came up. For example, I now cant access my Uni webpage, or more randomly, YouTube. It seems if my VPN connection is active, I can access them, but if I disconnect, then the requests just time out.

I thought this was just a problem with my desktop, but my laptop (which didnt have the VPN) cant access these pages either.

I've basically located the problem down to my router. If I bypass the router and plug the desktop straight into the modem, then I can access these pages. Does anyone know why a VPN would have altered something on the router? I'm guessing that when I try to access these pages, the router is trying to use my VPN connection or something (as you can see, I'm not well clued up on these). Would anyone know how to solve this problem? Any help would be greatly appreciated!

 

[Deebs]

Depending on the router in question there may actually be a defined route telling it to send all traffic down the vpn to the uni infrastructure and from there out onto the web.

Therefore, if the VPN is disabled the route out is dead and you get no traffic.

What router is it?

 

[Jeremiah]

It's a Sitecom router. I've tried reseting the router by the rest button and by the factory restore options, without success

 

[nath]

So if you enable the vpn on your desktop machine you can get back to the uni site and youtube - what about the laptop? If you enable the vpn on the desktop do things go back to normal on the laptop?

 

[Whipped]

Long shot, but is it possible that you have a proxy setup in IE that points to a proxy server that is only availble when you are connected via the VPN.

This wouldn't explain why you can connect when you bypass the router, but it's one extra thing to check.

To check, in IE, go to Tools...Internet Options. Click the Connections Tab and click the Lan Settings button. See if a proxy is in there.

 

[nath]

Also wouldn't explain why the laptop doesn't work, unless the laptop is set up to use ICS.

Very weird.

 

[smurkin]

Could it be a problem with the DNS in your router? If your provider's DNS is borked (the one entered into your router), you wouldn't be able to access webpages. However, your VPN would be using a separate DNS server for your uni....

Way to check....if the DNS is faulty, there is a good chance your e-mail will work, but web pages wont...

makes sense? (your isp isnt nildram is it? their dns servers are shocking at times)

 

[Dr_Weasel]

Since I 'upgraded' the firmware in my Netgear modem I lost access to a few websites such as Windows Update, Barclays bank, B&Q, but they were fine if I VPN'd into work and looked from there.

It turns out the MTU path discovery is now broken on the Netgear. If I set the max MTU on every PC behind the modem to 1458 it all works a treat. Have a search, but if you are on Windows a program called DrTcp can help you adjust it.