[Openswan Users] Road Warriors with same source IP Address

Paul Littlefield info at paully.co.uk
Tue Jul 18 06:29:23 EDT 2017

On 14/07/17 13:50, Gaiseric Vandal wrote:
> Assuming the remote user's have private IP class C subnet behind their ISP router/modem/firewall/gateway.   Assume each remote user has configured their PC with the same private IP address.  The initial connections to the VPN server should come from the public IP on the remote users' routers.        Are the remote computers linux or windows?   Is the tunnel for user1 actually going down, or does user1 just get disconnected from corporate resources because the routing changes?   I don't see how two VPN clients could have the same IP address any more than two LAN clients could.

I believe it the 'src' ip address (fakes shown) from this command...

$ ipsec look 2>/dev/null |grep 'dport'
src dst proto udp dport 1701
src dst proto udp dport 1701
src dst proto udp dport 1701
src dst proto udp dport 1701

I shall ask them if they just get disconnected from the Remote Desktop Server or whether the VPN connection drops as well.

The remote computers are Apple Laptops on OSX running the built-in VPN connection software and 'Remote Desktop' app. They both also have to run a Terminal route command...

$ sudo route -n add

Yes, the 2 users are in the same house with the same Sky router (which has a dynamic IP address) and are both on the router assigned Class C subnet.

> If you are using openswan  on the client in linux from the command line, I don't think you have an option to configure a virtual adapter (which would let the remote user have an IP address on the corporate LAN, therefore abstracting the remote user's real IP.)    Openswan in linux does have gui front ends for the client, but those never worked for me.   Instead I use shrewsoft as the linux gui vpn client, which may support virtual adapters.
> Are you using the strait IKE/IPSEC  VPN or are you using LT2P+IPSEC?


They are using the built-in VPN connector found in Apple OSX.


Paul Littlefield

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