I use an Efficient 5861 router on Covad ADSL with PPPOA LLC. It works fine but there seems to be an unsolvable problem--I am unable to send any outbound UDP packet. I even flushed out all remote and eth filters (not that they have anything to do with the problem as I can see) but no luck.
This router worked just fine on other network, so I don't think it suddenly has any hardware/software problem, I suspect there might be some network/architecture incompatibility?
If you use or have used similar routers on Covad, have you encountered the same issue? The easiest way to tell is to do a ping or traceroute and see if you get any result at all. I'd like to hear your experiences.