Linux – Multiple VPN connections on the same Computer at the same Time with the same Subnets

linuxpptproutingvpnwindows-server-2008

What's the best approach for such scenario? :

  • One machine „GATEWAY” SERVER with configured multiple VPN connections.
  • PC1, PC2, PC3, PC4 are the clients that with the same time wants to connect to different VPNs.
  • Some of the VPNs have the same IP SUBNET.

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PC1  ---RDP-->  „GATEWAY” SERVER  ---RDPoverVPN--> COMPANY „A” NETWORK

PC2  ---RDP-->  „GATEWAY” SERVER  ---RDPoverVPN--> COMPANY „B” NETWORK

PC3  ---RDP-->  „GATEWAY” SERVER  ---RDPoverVPN--> COMPANY „C” NETWORK

PC4  ---RDP-->  „GATEWAY” SERVER  ---RDPoverVPN--> COMPANY „D” NETWORK

How to prevent SUBNET IP address conflicts?
How to configure such thing?

At this moment „GATEWAY” SERVER runs with Windows 7 and it's not possible to use multiple connections at the same time.

Upgrade to Windows Server or Linux could solve this problem?

Or the better solution is to use some hardware „GATEWAY” SERVER?

Is it possible that different user accounts at „GATEWAY” SERVER could have separate VPN connections?

Best Answer

How to prevent SUBNET IP address conflicts? How to configure such thing?

1) Plan for it in advance, there are a lot of /24 networks available in 10.0.0.0/8 you don't have to use 192.168.0.0/24 for every site.

2) Buy or configure a device (e.g. a hardware firewall) which can do site to site VPNs, with Network Address Translation (NAT), to present the remote sites as if they have different addresses.

3) Narrow down the scope of the VPN, e.g. put one box at site A on 192.168.1.5 which you connect to by remote desktop, and do work from there. Have the VPN only connect to 192.168.1.5/32. On the next site, use 192.168.1.6/32, etc.

4) Have several "gateway" computers, one connected to each site. Switch between them.

Upgrade to Windows Server or Linux could solve this problem?

No, the problem is with network addresses, not operating systems.

Is it possible that different user accounts at „GATEWAY” SERVER could have separate VPN connections?

Multiple user accounts are not going to work well on Windows 7.

To be a true network VPN, multiple user accounts won't help, because the VPN will add routes at the network level, and they will apply system wide.