Question re: Multiple Simultaneous VPN Connection

Hi, bit confused on which is my next step to take to fix this.

My scenario is
4 Office PC - (all Xp Pro SP3)
2 Home PC - (all XP Pro SP3)

I have managed to connect the VPN from home pc to the office computer (this is a stand alone computer which i have all my files etc on and it has all printers etc connected to it, basically using as a server but not server if that make sense??)

the problem i have come across now is i can not connect more than 1 VPN back to the office (all user and passwords are correct and set up) it seems that i can only host 1 VPN at a time, is this a limitation on XP or the router?

Am i right for thinking i can buy a new router for the office that will host multiple VPN?

Many thanks for your advice

Bill
4 answers Last reply
More about question multiple simultaneous vpn connection
  1. I think it depends on the VPN server(host). I know at the firm I work at they only allow one VPN connection. I'm surprised you were able to do multiple VPN connections through one concentrator.
  2. Am only getting one Connection at time, The Client and the Host is Win XP Sp3,
  3. It's a limitation put in place by your VPN server on the office end. Check with the configuration at the office.
  4. Since it appears you are connecting PC-PC and not PC-vpn appliance your issue is likely NAT. You are somewhat lucky it even works with a single VPN, the router needs a special feature to support this.

    Without getting very detailed into why it does not work it is limitation of IPSEC and PPTP. This is very similar to why you cannot have 2 servers both using port 80 behind your router. You can only port map the outside port address to single machine. It much more complex for VPN, it is partially a mapping type issues but it is also in the security protocols themselves that detect sessions from duplicate ip.

    Pretty much the only way to fix this is to put the VPN on your router itself. Since this has direct control of the real IP address there is not a NAT problem. The other way to fix this is to run something like OPENVPN that supports running VPN over TCP. Generally they run it over SSL/TLS port 443 so it runs like HTTPS. This is much more tolerant but if you needed multiple machine in your office running VPN to multiple machines on the internet you would have to use different TCP ports for each.
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