and what DHT mean?
dht (distributed hash table) is not needed for your client to work.
It is only used if ALL the following apply
Tracker allows dht connections
You enable dht
at least one peer your connected to enables dht
Then if your client cannot connect to tracker, it will attempt to bypass tracker by connecting using dht.
I suggest you begin reading here…
http://en.wikipedia.org/wiki/Bittorrent
and have a read here too…
http://en.wikipedia.org/wiki/Distributed_hash_table
Suspect
Just one fine point – it’s not up to the tracker to allow/disallow DHT. The tracker isn’t involved in any way. It is the torrent creator, at the time of creation, who chooses whether the torrent will support DHT or not.
Some tracker sites have rules requiring that posted torrents be created with the “private” flag, disallowing DHT and PEX, but that’s administrative, not technological. If a torrent were posted to such a site and allowed DHT, then DHT would work regardless of the tracker’s actions short of removing the torrent.