netstat -anp --tcp --udp | grep LISTEN
the port glftpd was previously running on, was not in the list anymore and also ps aux | grep glftpd did not show the process. The error "service/protocol combination not in /etc/services: glftpd/tcp" could be seen when restarting xinetd
sudo /etc/init.d/xinetd restart
while tailing syslog
tail -100f /var/log/syslog
All that was missing was a entry in /etc/services at the end.
# Local services
glftpd 10087/tcp # glftpd
First I thought the 10.04 upgrade process was flawed but then I remembered that Ubuntu actually asked me to keep or overwrite some files which I had modified in 8.04. I almost always decided to overwrite the files, except for some local Apache modifications. Apparently /etc/services was one of the files that had changed.