TAP UDP bridge questions for games networking.

Target

Hello Guys!

I would like to ask for your help in the next problem. I have a router with Tomato USB-VPN firmware. I set up a VPN server on it. I would like to insert my clients to my network so I tried bridge mode I want to play games with my friends. These games use broadcast address to communicate each other. I used TAP adapter with UDP both server and client side, and I generated the keys to use tls connection. Redirect_gateway setting not set so they can use their internet connection during playing games with together. We turned off the firewall on every pc to make sure everything works fine. I opened the port on the router and the the VPN connection worked fine, they get IP address from my local subnet, and we saw the netbios network shares. It seemed that everything works fine.

Then when I created a game server from local network side and they didn't see it.
When any vpn client created a server I can see and connect to it but another vpn client can't see that server.

The Same problem when Client to Client option disabled/enabled on Tomato.
When I check connection with tcpdump both client can send messages to broadcast.

Maybe you have some recommendation or idea what did I wrong.

Thanks a lot for any help!

Settings and network:

janjust

check out https://forums.openvpn.net/topic7319.html to see if that helps you - even on a fully functional bridged setup windows games sometimes don't want to properly broadcast traffic.

Target

Thanks for help!
So if I am right, the main problem is that WinXP &/or Win7 forwards the broadcst packets to the default network adapter.
Here is my client configuration:

client
dev tap
proto udp
remote mydomain.address 1194
ca ca.crt
cert petya.crt
key petya.key

resolv-retry infinite
nobind
persist-key
persist-tun
comp-lzo
verb 3

In this case the physical adapter will be the default adapter.
But what happens if I add the following network configuration?

redirect-gateway

In this case the TAP adapter will be the default because all the network traffic will be forwarded to it.
Am I right ?
Anyway I will take a try at weekend.

Edit:

If this configuration edit solve this problem, then it can be added to wish list or idea list to add a new command to the new version of VPN client like redirect_broadcast and then broadcast can be forwarded to default, TAP. or both adapter.

And all of the other packages can go through the default internet connection.

janjust

In this case the TAP adapter will be the default because all the network traffic will be forwarded to it.
Am I right ?

yes it will be the default IP network adapter; whether an application decides to send broadcasts to it is a different matter : that's up to the OS and the application

If this configuration edit solve this problem, then it can be added to wish list or idea list to add a new command to the new version of VPN client like redirect_broadcast and then broadcast can be forwarded to default, TAP. or both adapter.

if you can come up with a way to reliably do this in Windows then I'm sure somebody will want to add it as a feature; the problem is that this is beyond the control of OpenVPN: if an application decides to send broadcasts to the default LAN adapter only then it will do so.

Target

janjust wrotecheck out https://forums.openvpn.net/topic7319.html to see if that helps you - even on a fully functional bridged setup windows games sometimes don't want to properly broadcast traffic.

If I use TUN "Routed" server then will I able to use 255.255.255.255 special broadcast between the clients ?