OpenVPN GUI v10 - multiple VPN connections

zatp

Dear All,

At the beginning apologies if similar topic alredy exists.
I already read few topics related to "multiple VPN connections" however I couldn't find the right answer.

Background

I have a Win7 PC which is running OpenVPN GUI V10. My goal is to use it as a VPN server (gateway) which allows me to establish multiple VPN connections and as result remote clients can talk to each other.
The PC is not behind the ISP NAT that means there is no issue with incoming traffic (request from client -> server).
I'm aware that OpenVPN has a dedicated product "OpenVPN Access Server" however I would like to check if I'm able do it with Open VPN GUI.
On the PC which is running server configuration I've configured two servers configurations (ex. server.ovpn; server2.ovpn)
I've added additional TAP interface to allow two connections (not sure if it is really required)

Client1 config

dev tun
remote <publicIP>
proto udp
port 1194
ifconfig 10.3.0.2 10.3.0.1
secret secret.key
persist-tun
persist-key
keepalive 10 120
cipher AES-256-CBC
comp-lzo
verb 1

Server1 Config

dev tun
local <localIP>
proto udp
port 1194
ifconfig 10.3.0.1 10.3.0.2
secret secret.key
persist-tun
persist-key
keepalive 10 120
cipher AES-256-CBC
comp-lzo
verb 1

Client2 config

dev tun
remote <publicIP>
proto udp
port 60500
ifconfig 10.4.0.2 10.4.0.1
secret secret.key
persist-tun
persist-key
keepalive 10 120
cipher AES-256-CBC
comp-lzo
verb 1

Server2 Config

dev tun
local <localIP>
proto udp
port 1194
ifconfig 10.4.0.1 10.4.0.2
secret secret.key
persist-tun
persist-key
keepalive 10 120
cipher AES-256-CBC
comp-lzo
verb 1

Could you please advice me how it should be configured?
Is it possible to configure ex. one server config which will allow multiple VPN connections ?
In addition what about IP addresses for VPN users. Is it possible to run a DHCP server?
If both clients could get an IP address from one IP range, there should be no issues with communication because all devices will exist in one subnet.
However if both clients has an IP address from different IP subnets (above scenario), how can I provide communication between two VPN subnets.
Is it enough to add in a server config command to "push route x.x.x.x" so the client will be able to communicate with other VPN device ?
I would like to avoid creating bridges etc.

Your help is greatly appreciated.
Many thanks

TinCanTech

zatp wroteIs it possible to configure ex. one server config which will allow multiple VPN connections ?

Simply read through the example server and client config files found in
C:\Program Files\OpenVPN\Sample-config

zatp

Hi TinCanTech
Apolgoies for that.
I should do it at the beginning.

I'm able to connect both clients to my VPN server however I'm not able to reach both peers.

Client 1 receives an IP address 10.3.0.6/30 (10.3.0.5 GW) based on Common Name
Client 2 receives an IP address 10.3.0.10/30 (10.3.0.9 GW) based on Common Name
Unfortunately from above clients I can't ping DG (10.3.0.5&9) however I'm able to reach VPNserver itself 10.3.0.1

In this scenario we have two virtual subnets 10.3.0.4/30 and 10.3.0.8/30
To make it working OpenVPN needs to route somehow the traffic orignated from ex 10.3.0.4 -> 10.3.08 and vice versa.
Unfortunately I'm not sure what else needs to be done. I've enabled forwarding IP via regedit but still no luck.
Windows Firewall was disabled during the tests.
I tried to create a static route on both clients but still without luck.

I will appreciate your help here.
Many thanks

TinCanTech

zatp wrotefrom above clients I can't ping DG (10.3.0.5&9) however I'm able to reach VPNserver itself 10.3.0.1

Those IPs (.5 & .9) are not functional addresses they are only VPN end points and so do not respond to ping.

zatp wroteTo make it working OpenVPN needs to route somehow the traffic orignated from ex 10.3.0.4 -> 10.3.08 and vice versa

Time to read the HOWTO (all of it) :
HOWTO: Expanding the scope of the VPN to include additional machines