> I assigned an IP address to LAN interface and was able to get into 
> WebGUI. Then I went to 'OPT1' page and setup bridging between WAN and 
> OPT1. So far so good. Then I tried to enable OPT1 interface and as soon 
> as did this m0n0 GUI stopped responding although traffic between WAN and 
> OPT1 was Ok. I also wasn't able to ping LAN interface. Rebooting m0n0 
> didn't help and I was forced to reset config. I played with firewall 
> rules and allowed any to any on all interfaces but no success.


I would have done it in that order:

   1 - enable OPT interface
   2 - bridge between OPT and WAN setup

It seems you've done it in the reverse order. I don't know if it's 
relevant in your case, but who knows?...

-- Vincent