Matthew Dillon has added transparent bridging, mostly to overcome issues with the AT&T DSL modem he’s using. With this non-default feature, IP packets retain the original MAC address when retransmitted through a new interface.
A running description of activity related to DragonFly BSD.
A nice feature, to be sure (particularly when using pf as an “emergency” firewall without disrupting an existing network), but I can’t visualize why he needed this do deal with a DSL modem :) My parents have U-Verse, and it does have its issues, but I connected their old wireless router’s WAN port to one of the AT&T’s router’s LAN ports. They are not big gamers or anything, and aren’t running their own server, but otherwise it works fine, and they have total control over access to their home network.
I think this is because Matt’s trying to multiple routable IPs through the U-Verse device. It’s not a single endpoint for a NAT device as it would be for your parents. I’m not the one using it so I’m not 100% sure.