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OpenVPN - custom Private Network?

Posted: Wed Nov 02, 2022 9:29 pm
by stormy
Noticed that upon connection to VPN a message appears, and this interface is created:

Unknown adapter OpenVPN TAP-Windows6:

Connection-specific DNS Suffix . :
Link-local IPv6 Address . . . . . : fe80::64f6:7204:c55d:25f3%45
IPv4 Address. . . . . . . . . . . : 10.8.8.6
Subnet Mask . . . . . . . . . . . : 255.255.255.0

the question, how does one change the subnet range from 10.* to something in 172.16.*?

As described here: https://openvpn.net/community-resources ... e-subnets/
there are 3 ranges, I've got many conflicts on the 10.* and 192.168, so would like to see if the TAP interface can be configured to 172.16.*?

Thanks.

Re: OpenVPN - custom Private Network?

Posted: Wed Nov 02, 2022 9:40 pm
by Pippin
The adapter is configured by the server configuration.
It is the tunnel subnet (10.8.8.0/24 in your case) as depicted here:
https://community.openvpn.net/openvpn/w ... gConflicts

Re: OpenVPN - custom Private Network?

Posted: Thu Nov 03, 2022 12:04 am
by stormy
Does that mean I need/at the mercy of the VPN Service provider(s)? I looked at the vpn client config script, could not find it there.

Do they "transmit" the tunnel subnet to be used and it is outside of my direct control at the client/OS side? Very strange that the server will force a subnet onto the Client side.... what if not all clients want the same subnet? shouldn't that control be at the hands of client?

If so, what should I say to a VPN provider to change this private subnet?

Does anyone know if there are VPN providers that allow such selection? (not sure if company names are allowed to be discussed, maybe PM if that is not allowed)

Thanks.
Stormy.

Re: OpenVPN - custom Private Network?

Posted: Thu Nov 03, 2022 12:45 pm
by ordex
Yeah, basically this is controlled by who runs the server (the provider). To be honest I hardly believe they will change the subnet just for one customer, but it's worth asking. The chosen subnet is normally hooked into technical decisions made by the provider so, I don't think this can be "selectable".

Are you using the 10.8.8.0/24 subnet somewhere else?

Re: OpenVPN - custom Private Network?

Posted: Fri Nov 04, 2022 2:35 pm
by stormy
it seems the 10.8.* changes over time, so not same number, sometimes 10.14, etc.

I have (many) 10.* routes to another network on same PC just different NIC, was thinking that split-tunnel would allow running both and keeping traffic separate..

however, looking further it seems that issue is probably more DNS related, in that the Split-Tunnel splits the (udp/tcp) traffic, BUT, all the DNS requests are going on to the VPN as well, as such name resolution for other networks are not possible!! I think I need something like "split dns"? so that if a name does not resolve in the VPN it would go to the other defined DNSs.. OR, only certain apps would use the vpn-dns, all others will use other dns's on the server.

Thanks for any tips...
Stormy.