This has happened for me under Ubuntu 10 , but may also happen some where else.

Every thing was working on my system fine, until one day I noticed that the tftp server (tftpd-hpa) is no more working.

Investigating the log produced by tftpd-hpa, located in /var/log/daemon.log , I have found this messages being produced whenever I try to connect to the tftp server.

in.tftpd[2401]: cannot set groups for user nobody ….

Looking at the list of running processes at the same moment, I could see that

nobody    2494  0.2  0.0  10636   740 ?        Ss   11:43   0:00 in.tftpd var/lib/tftpboot -s

the tftp server is being run as the nobody user. As a solution, I changed this file:

/etc/xinetd.d/tftp

And as the user, I selected “root”:

service tftp
{
protocol = udp
port = 69
socket_type = dgram
wait = yes
user = root
server = /usr/sbin/in.tftpd
server_args = var/lib/tftpboot -s
disable = no
}

restarting the xinet.d and also tftpd-hpa, every thing is again working fine!

Mohammad S. Sadri.