Linksys Router to Internet to VPN Then Connect to Remote using Remote Desktop Connect

[easikwilson]

I have a network (192.168.1.xxx) on private side of Linksys WAP DSL/Cable Router which is connected to Internet via Cable Modem. I would like to establish a Remote Desktop Connection to a server located on the private side of a remote network (also a 192.168.1.xxx network) that is connected to the internet with a 3COM DSL Router with built-in VPN. I can currently establish the VPN connection through my Linksys equipment, but cannot connect to the server using Remote Desktop Connection while using the Linksys router on my end. If I remove the Linksys router on my end and use a direct connection from my local cable modem to a single PC, I can establish the VPN conenction AND I can connect to the remote server using Remote Desktop Connection. There are no known IP address conflicts between the two private networks, but it seems like when I have the Linksys router installed on my end that the connection request for Remote Desktop Connection may not be leaving my local private network, so I eventually get a "fail to connect error" just like you do if I use the wrong IP address when attempting to connect using the single PC approach without the Linksys router.

Any Ideas???

[M_Six]

That's right, because your local network is 192.168.1.xxx and so is the remote network. Your Linksys router doesn't know the difference between your local 192.168.1.xxx network and the remote .1.xxx network. So when you go looking for a connection to 192.168.1.xxx on the remote side, the Linksys router is only searching your internal network.

We tried to set up a similar deal at work using two Linksys routers. The remote PC must have some address other than 192.168.1.xxx. Try putting the remote router and PC on 192.168.2.xxx.

[easikwilson]

I went ahead and changed the address of one of the systems, and yes it does work now. Thank You !!

Is there any way known to have both networks at the same address?

[Siliconjunkie]

Nope, they must be 2 different networks if they are to talk to each other.

[meese]

Silicon,

If the server on the remote side is a W2K DC and also acting as a DHCP server, it will assign an IP address to the client VPN machine automatically depending on how you have RAS configured. And when you VPN from the client, even though the private ip is say 192.168.1.23, the remote VPN server sees the public IP assigned by the client ISP. And when you configure the client you tell it to use the public ip of the server ISP. So I'm confused as to why you couldn't have the same private ip in use on each end.

[Siliconjunkie]

If the server on the remote side is a W2K DC and also acting as a DHCP server, it will assign an IP address to the client VPN machine automatically depending on how you have RAS configured.

Agreed

And when you VPN from the client, even though the private ip is say 192.168.1.23, the remote VPN server sees the public IP assigned by the client ISP.

True, if I am reading it right

And when you configure the client you tell it to use the public ip of the server ISP.

Correct as well

Ok, let me whip up a quick diagram to explain. I will edit with a pic.

Ok, pictures. You should be able to read the text

Without VPN
With VPN

The problem isnt with the Client seeing the VPN server. Which is what I think you were thinking. The problem is routing, since you now have overlapping address space in your virtual network.

All the quotes were just a way for me to break it up into thoughts/statements.

[meese]

This is where I'm confused:

Say you have a home network in a domain environment. And a work network also in a domain environment. Your DHCP scopes are identical (192.168.1.0). (I have this setup but my work DHCP scope is 192.168.0.0 and home is 192.168.1.0, and I VPN back and forth all the time) So I can't test the same scope scenario unless I changed one of the scopes. Anyway if my home IP address is 192.168.1.100 and I VPN into work. RAS is configured to use 192.168.0.30-35 for VPN connections. So the IP address assigned for the connection is different than the home IP address. So even if you have 192.168.1.100 leased on the work network, and your home IP is also 192.168.1.100, when you connect the server will assign the VPN connection an ip that is different then 192.168.1.100.


Does that make sense?

[easikwilson]

>>My original Dilemma....

[quote]Originally posted by easikwilson
[b]I have a network (192.168.1.xxx) on private side of Linksys WAP DSL/Cable Router which is connected to Internet via Cable Modem. I would like to establish a Remote Desktop Connection to a server located on the private side of a remote network (also a 192.168.1.xxx network) that is connected to the internet with a 3COM DSL Router with built-in VPN. I can currently establish the VPN connection through my Linksys equipment, but cannot connect to the server using Remote Desktop Connection while using the Linksys router on my end. If I remove the Linksys router on my end and use a direct connection from my local cable modem to a single PC, I can establish the VPN conenction AND I can connect to the remote server using Remote Desktop Connection. There are no known IP address conflicts between the two private networks, but it seems like when I have the Linksys router installed on my end that the connection request for Remote Desktop Connection may not be leaving my local private network, so I eventually get a "fail to connect error" just like you do if I use the wrong IP address when attempting to connect using the single PC approach without the Linksys router.

>>My response after trying to change one of the network IP settings...

I went ahead and changed the IP address (from say 192.168.1.xxx to 192.168.22.xxx) of one of the systems, and yes it does work now. Thank You !!

Is there any way known to have both networks at the same address?

>>New Information to aid with discovering a possible way to keep the IP addreeses of both systems the same.

In my original scenario, both networks were set at 192.168.1.xxx, and when I would VPN in from my cable-modem internet conenction, the gateway/router on the remote end (which has built-in VPN functionality, there is no "server" machine handling the VPN) would dole out an IP address of 192.168.1.189 (with a subnet mask of 255.255.255.255). I was able to see this information by using the IPCONFIG command from the command line. I could ping IP addresses (that existed) in the IP range 192.168.1.xxx on my end only, I could not ping any IP address on the remote network at all. Once I changed my smaller network address to 192.168.22.xxx and repeated the VPN conenction, I was once again assigned 192.168.1.189 by the remote network when connected by VPN, and now I could ping all known IP addresses in the remote network, including the Windows 2000 terminal services server to which I wanted to connect with remote desktop.

What I am looking for a solution to is finding a way to have both networks at 192.168.1.xxx (with no conflicting IP addresses on either end) and be able to VPN into the remote network and have my cable/DSL gateway/router allow me to both connect via VPN, but then see the IP addresses on the remote network. Once I can see the remote networks IP addresses, it seems I have no problem with conencting via Remote Desktop Connection to the Windows 2000 terminal services server.

Hope this helps...

[vze2rdgy]

I had a similar situation when both (dsl & my private) networks had same IP class (192.168.1.x). What I did was, I went to my VPN client network connection properties, chose TCP/IP properties, clicked "advanced" button, and unchecked "Use default gateway on remote network". After that I was able to remote desktop to the pc in my private network.

[nemowolf]

Originally Posted by easikwilson

What I am looking for a solution to is finding a way to have both networks at 192.168.1.xxx (with no conflicting IP addresses on either end) and be able to VPN into the remote network and have my cable/DSL gateway/router allow me to both connect via VPN, but then see the IP addresses on the remote network. Once I can see the remote networks IP addresses, it seems I have no problem with conencting via Remote Desktop Connection to the Windows 2000 terminal services server.

Hope this helps...

There is not a way to do this. To make it brief your router sees a ping request coming in from 192.168.1.2 to 192.168.1.x on your remote network. Because the router sees this as a local address it does not let the traffic leave and instead looks for a local device at that address. That is why you need a diffrent ip scheme at each location to ensure that the router knows to let the traffic transmit beyond itself.