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Old 10-10-2009, 09:32 PM   #1
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Registered: Jul 2007
Posts: 27

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PoPToP not allowing access to server-side network via VPN connection


I'm struggling with an issue I'm having with my PoPToP server on Ubuntu 9.04.

I've got two servers - one at home and one at my office. Both are identical computers and are both running Ubuntu Server 9.04 64-bit. The problem is that the server at the office is not allowing access to other machines on the network. However, everything works fine with the VPN server on the one at my house.

The setup for the server at home is:
-AT&T 2wire U-Verse gateway with a WRT54G running DD-WRT in the DMZ
-The WRT54G address is, the server is
-PoPToP is setup with a server-ip of and a remote-ip of

The setup for the server at the office is:
-AT&T 2wire DSL gateway with a WRT54GL running DD-WRT in the DMZ
-The WRT54GL address is and the server is
-PoPToP is setup with a server-ip of and a remote-ip of

When I connect to the VPN at home, everything works perfectly - I can access the server and any other device attached to the server's network without problem via the VPN. However, when I connect to the VPN at the office, I can only access the server itself. I cannot ping any other machine on the server's network through the VPN.

I set the server at home up about 4 or so months before the office VPN, but I'm pretty sure I did the exact same thing, and I don't recall doing anything strange to get the VPN working properly.

I've already made sure all the port forwarding and settings are correct on the routers.

Does anyone have any ideas about what could be happening here? If it matters, I've tried using an XP and a Vista machine as the client, both behind two completely different networks and they do the exact same thing.

Old 10-10-2009, 09:40 PM   #2
LQ Newbie
Registered: Jul 2007
Posts: 27

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One thing I was just thinking about, is could it have something to do with the IP address range at the office? Would I be better off changing the IP address range to something like at the office?

Thanks again!
Old 10-11-2009, 11:11 AM   #3
LQ Newbie
Registered: Jul 2007
Posts: 27

Original Poster
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Well I seem to have figured out the problem. IP Forwarding needed to be enabled. If anyone else is experiencing the same issue, take a look at the last two posts here:


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