Using Guarddog I have 'NAT OK' in Azureus but DHT remains firewalled. In Guarddog I have BitTorrent Peer and BitTorrent Tracker enabled in Internet and Local as well as a 5 digit port [udp and tcp] especially for Azureus. Same 5 digit port [udp and tcp] is enabled in router. In fact this is how I've set things for Azureus for quite some time with no problems. In last few days DHT remains firewalled in Azureus. Any ideas? Am having same problem in Kubuntu and Mepis as well. Anyone know what's up? Like is it really an Azureus problem or a DHT problem?

I also tried:

#aptitude purge azureus
reboot
#aptitude install azureus

Nothing changed.

Are you using standard ports? It's possible that your ISP is blocking BitTorrent ports.
You could also try putting your machine as the DMZ in your router - that should tell you if the problem is with your router's forwarding configurations or not.
What happens if you try it with IPTables disabled?

My isp is Comcast. I've never seen or heard of them blocking ports. I HAVE moved [about a mile] and either Comcast or DHCP assigned me a new IP and Netmask which I've changed in my router. Also, FWIW, KTorrent in PSLinuxOS 2007 is working fine [they don't have Azureus in their repos yet]. I've tried different ports as well. No luck. I suspect it has something to do with a router OR gateway setting but I don't know/remember what to do to fix it yet. OR it's a bug in Azureus, 'cause if it was a router/gateway setting I probably wouldn't be getting NAT OK.