VPN connection loses Internet

By Healer ·
As soon as a VPN connection is established, the local network connection and the Internet connection are lost. Soon later, the local network connection recovers but the Internet connection will never resume until the VPN is disconnected.

It happens on Windows 7 systems and Vista system. What could I have missed?

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VPN security

by TobiF In reply to VPN connection loses Inte ...

The term VPN means virtual private network.

The idea is that you use internet to virtually place your computer inside the lan od the VPN host.

In order to avoid your computer becoming a bridge between the internet and the LAN, to which you connect, your computer will add routing rules that cut direct access between your computer and internet (except for the VPN tunnel, of course).

If the LAN you connect to via VPN lacks access to internet (or blocks access to internet for incoming VPN connections), then you'll not reach internet.

There are ways to add routes from your computer to the internet. But before you start plaing with those things, you should check with the owner of the network you connect to, whether they allow you to do this, or not.

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I thank you for your explanation.

by Healer In reply to VPN security

I had guessed it that must have been the reason. I have also found out how to get the local LAN network back. I am testing it from my test system in my office anyway.

The reason I ask about it I have a VPN connection sort of keeps playing up, dropping randomly. The administrator over the other end claims that there is no problem for other people connecting to it. I am just desperately looking at every possible causes. I have already enabled various types of VPN at the NETGEAR router WNR 2000. I have even "OPENed" the NAT FILTERING.

I wonder where else I should look at.

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MRU? Throttle? RFI?

by TobiF In reply to I thank you for your expl ...

An outgoing VPN connection from your computer should not be any strange for your router. If you have opened it up, then you better plug all the surplus holes you have opened.

VPN adds a little overhead information to each packet. If you're unlucky, this will make each outgoing packet just a little bit too big, so it will be broken into two packets. This creates unnecessary work for your computer and the router.

I hope someone will step in and tell us where you can adjust the maximum packet size at root.

Otherwise, if too many packets drop out of the outer VPN connection, then it may break. If you happen to use the full capacity of your internet line (say, a couple of bittorrent clients running in unlimited settings), then you better make sure, one wy or another, that you reserve enough capacity for your VPN connection.

If you're using wifi between your computer and router, try connecting via cable and see if this helps.
Radio frequency interference (and or ethernet traffic collissions) could kill enough packets to break your vpn link. This might be a microwave oven, DECT phone or something, but could also be that your network uses not the same, but adjacent channels as your neighbour (1-2 channels away) Metageek inSSIDer will show you what wifi networks are visible from your computer, what channels they're on (and how wide the channels signal is, depending on its signal speed) For 802.11g, it's best to maintain 5 channels difference, the general recommendation is to only use channels 1, 6 and 11 (although lots of home routers totally ignore this).

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What is MRU?

by Healer In reply to MRU? Throttle? RFI?

I suppose you mean MTU, maximum transmission unit. I have already done it and reduced the size to the maximum workable.

RFI, do you mean radio frequency interference? The connection is on Ethernet anyway.

Once I get it working reliably I will test and disable as many other options on the router as possible.

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You're guesses are correct.

by TobiF In reply to What is MRU?

Yes, I should have written MTU, my mistake.

Yes, I meant radio interference. I decided to use this abbreviation as a secret sign to other radio amateurs, who may be listening... uh-oh reading this. Anyway, it was a guess that wasn't applicable this time.

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Address conflicts?

by TobiF In reply to I thank you for your expl ...

If the local network at the VPN host has the same addressing range as your home network, then your own computer will have problems routing your packets to local addresses.

So, if your home network uses 192.168.1.x or 192.168.2.x, try to ditch it away to, say, 192.168.137.x or some other range within 192.168. (Keep the network mask of When you do this change in your router, you'll most probably have to change the URL to the router administration interface manually.

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I do not think so.

by Healer In reply to Address conflicts?

The range at the client's is 10.0.0.x and that at the VPN host is 10.22.1.x. Both have the mask

By the way, what do you mean by "When you do this change in your router, you'll most probably have to <u>change the URL to the router administration interface manually</u>"?

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You may need to manually change the URL in your browser

by TobiF In reply to I do not think so.

Sorry. That expression looks more strange, than necessary. I simply meant that when the IP address of everyone changes, you usually need to manually change the URL address in your own browser.

It's good that they have different address spaces. I just wanted to check.

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contact your provider

by vpnandroid In reply to VPN connection loses Inte ...

that cause by ip nat translation on your provider was bad
try to move to another provider
search google : vpn android services


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