[tor-talk] Why does tor open UDP ports?

[Stephan]

Hi,

I'm a little bit confused as to why tor opens two UDP ports (one ipv4 
and ipv6 each) on my server. The port numbers seem to be random. The 
output from 'netstat -lnup' is as follows:

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         
State       PID/Program name
udp        0      0 0.0.0.0:41512           0.0.0.0:*                    
        8456/tor
udp6       0      0 :::36206                :::*                         
        8456/tor

After a little search I suspected those ports to be used for DNS 
functionality - but the config option "DNSPort 0" in my torrc did not 
deactivate those ports and the socks proxy is disabled as well. 
Furthermore I would have expected such ports to be opened for local 
connections only, but they accept connections from the whole wide world 
...

So why does tor open those ports?


-Stephan