transmission unable to connect to trackers, utorrent is

[thereptilehouse]

hi, apologies - i couldn't find a thread where this problem was answered. i'm trying to download some torrents from a public tracker, but transmission has "announce error: could not connect to tracker" for all the entries. i do get some peers (i presume from peer exchange, or similar?) but they're slow and on some torrents they don't have the whole file available.

the weird thing is that utorrent can connect to the same trackers for those torrents perfectly, and on the same port, so i'm stumped as to what i'm doing wrong.

i've forwarded the port i'm using to my local IP, tried selecting and unselecting automatically map port and nothing seems to help. i realise this is probably a stupid question, but i'd love it to be fixed because i love transmission and would really rather not have to switch to utorrent.

[fuga]

I've seen similar, too. Anyone?

[cbrace]

I am (I think) seeing something similar.

Private trackers work fine.

HTTP-based public trackers seem to work OK too.

UDP-based public trackers never work. No connection.

Magnet links, which all seem to use UDP-based trackers, hence likewise never work. If I upload a magnet link via Add URL, it never gets past "downloading metadata".

Using the same network connection, another BT client, deluge, doesn't have this problem. I upload a magnet link, it can usually download metadata within a few seconds and begin downloading the file, if there is a seeder.

[cbrace]

I have been further experimenting here.

In my setup, UDP works fine when transmission has a direct network connection. I open port 51413 (TCP) on the firewall. It can connect with UDP-based trackers no problem.

However, when I connect through a VPN, UDP seems to break. The port is forwarded by the VPN server, and the client indicates that the port is open, but the client can't seem to connect to UDP trackers.