Comment 4 for bug 298314

I saw this behavior with empathy (2.32.1) on Ubuntu 10.10 attempting to send files to empathy 2.30.3 on Ubuntu 10.04 over link-local XMPP.

The 10.04 has no firewall, the 10.10 has ufw with 5298 open (both TCP and UDP). Messaging between the two computers is OK.
To the best that can find on the net XMPP file transfers have port 8010/TCP assigned to them (https://secure.wikimedia.org/wikipedia/en/wiki/List_of_TCP_and_UDP_port_numbers , http://stackoverflow.com/questions/3452161/which-ports-does-xmpp-uses). So just in case I did open 8010/tcp on the 10.10 machine before attempting the trasfer. Nada... Nothing! After some timeout both sides canceled the transfers and blamed the other side for the failure.

Disabling the ufw firewall however did get my files through. So I captured the traffic in wireshark and it turned out that in each of my three tests my 10.10 machine was using a different port. In chronological order:
* 54737
* 40467
* 42298

I don't think I can master such a ufw rule to let empathy/telepathy send files through any port number picked up at random. So unless it's designed to require no firewalls (as it is designed to support no otr messaging), I think it either has to use the assigned port, or (better) it should allow this to be configured in some humanly way, or it should take care for opening and closing the port its dices have picked up for the transfer.

Please advise if further any details are needed. The details on the versions of related packages follow.
For the 10.10 machine:
andrew@sat11:~$ dpkg -l | grep telepathy
ii libfolks-telepathy0 0.1.17-0ubuntu2
ii libtelepathy-farsight0 0.0.14-2
ii libtelepathy-glib0 0.12.0-0ubuntu1
ii libtelepathy-logger1 0.1.5-1ubuntu1
ii python-telepathy 0.15.17-1
ii telepathy-butterfly 0.5.14-1
ii telepathy-gabble 0.10.0-1
ii telepathy-haze 0.4.0-1ubuntu0.1
ii telepathy-idle 0.1.6-1
ii telepathy-logger 0.1.5-1ubuntu1
ii telepathy-mission-control-5 1:5.6.0-1
ii telepathy-salut 0.3.12-1
ii telepathy-sofiasip 0.6.3-1
andrew@sat11:~$ dpkg -l | grep empathy
ii empathy 2.32.1-0ubuntu1
ii empathy-common 2.32.1-0ubuntu1
ii nautilus-sendto-empathy 2.32.1-0ubuntu1

For the 10.04 system:
ivanov@ivanovi:~/Плот$ dpkg -l | grep telepathy
ii libtelepathy-farsight0 0.0.13-1
ii libtelepathy-glib0 0.10.1-1ubuntu2
ii python-telepathy 0.15.17-1
ii telepathy-butterfly 0.5.11-0ubuntu1
ii telepathy-gabble 0.8.12-0ubuntu1
ii telepathy-haze 0.3.4-1
ii telepathy-idle 0.1.6-1
ii telepathy-mission-control-5 5.3.2-3
ii telepathy-salut 0.3.11-1
ii telepathy-sofiasip 0.6.2-1ubuntu1
ivanov@ivanovi:~/Плот$ dpkg -l | grep empathy
ii empathy 2.30.3-0ubuntu1
ii empathy-common 2.30.3-0ubuntu1
rc libempathy-gtk28 2.28.1.1-0ubuntu1
rc libempathy30 2.28.1.1-0ubuntu1
ii nautilus-sendto-empathy 2.30.3-0ubuntu1