How does one know which process/kerneldaemon that own specific udp ports?

The UDP ports does not show up in
# lsof -i udp

# netstat -anp shows
udp        0      0 0.0.0.0:911                  0.0.0.0:*                               -

How do you get to know what hooked UDP 911?

Helpful hints would be greatly appreciated
Chris