Does using VPN defeat point of bridging interfaces ?
I have my Ipad connected to separate access point which is fed from an OPT interface bridged to another where my Squeezebox Server resides. This is to allow the "Ipeng" app to work controlling the server and itself receiving the audio streaming. The wireless security is WPA2/AES and I use a 40 character mixed symbol password so no real need for VPN I suppose ( I am only client on this AP as opposed to another AP on separate OPT where all LAN resources blocked)
Point is, the VPN setup involves subnet re-direction(s) so trying to feed one of bridge member interfaces through one would surely break broadcasting/multicasts wouldn't it ?
It seems like an excessively complex setup, unless you're doing it for educational purposes. :)
Usually you only need mulicast for server discovery and it looks like ipeng has a manual option for that.
Partly educational, yes , I tried to get pptp vpn going on a second system to see what's involved but haven't got it working yet. As far as the Ipad is concerned I know of the manual server discovery on Ipeng which I had to use to connect to my differently subnetted "public" wireless before I locked it down and removed any access other than the Web. I tend to power down the Ipad completely after using it maybe it still sees the Squeezebox Server if only "sleeping"
Hmm, I don't think I've fully understood the problem here. :-
Are you asking whether multicast over OpenVPN is possible?
Perhaps: http://forums.openvpn.net/topic8036.html is relevant.
Or are you trying to solve some ipeng problem?
Edit: You may use the IGMP proxy to multicast between subnets, possibly an easier solution. Perhaps! ;)