Not an expert myself and never work with it consistent enough to instantly know what's wrong.
Recently we setup a new VM of Gentoo in an attempt to create a simple bridge between our two networks.
Currently we are just using a simple iptables chain to forward traffic destined for the other network across the interfaces.
This seems to work pretty well.
The next challenge is to see if we can route multicast traffic, in particular upnp DLNA.
However this doesn't appear to be working.
Anyone know of a good method to accomplish this?
Background setup:
Full network running behind a Shaw[ISP1] Router on a 192.168.1.0/24 network.
Full network running behind a Telus[ISP2] Router on a 192.168.5.0/24 network.
VM ESXi Server running with dual NICs, one on each network.