Joined: 09 Jul 2013
|Posted: Wed May 30, 2018 20:47 Post subject: HINT: Cross-VPN broadcast discovery (I used for Retrospect)
|Here's a simple hint for those who use DD-WRT together with OpenVPN to link subnets into a single LAN.
Our Retrospect backup software uses subnet broadcast discovery to find all client machines. It's easy to add all of the required subnets to Retrospect... but the broacasts (on port 497) were not getting through.
I'm using a Kong build. From SSH:
1) Ensure "bcrelay" is available. Just attempt to run bcrelay from the command line. If you get some help, you're in good shape.
2) You need to know your OpenVPN virtual device name at the *client* end of the link. It's listed in the current OpenVPN status. Mine is "tun1"
3) At the *client* end of the link, add a command to the Admin Startup command list:
bcrelay -i tun1 -o br0 -d
This relays all (UDP) broadcasts received from the other end of the VPN link, out onto your local (br0) LAN.
For me, that was sufficient.