Description of problem: | # ps axu | ntp 2018 0.0 7.6 4756 4756 ? SL 10:28 0:00 ntpd -u ntp -p /var/run/ntpd.pid | | # cat /proc/2018/status | Name: ntpd | ... | Uid: 38 38 38 38 | Gid: 0 0 0 0 | FDSize: 32 | Groups: 0 1 2 3 4 6 10 As you see, the privileged group-memberships are not dropped. The gid itself can be assigned by calling it with '-u ntp:ntp' instead of '-u ntp': | # ps axu | ntp 2252 0.0 9.1 5660 5660 ? SL 10:54 0:00 ntpd -u ntp:ntp -p /var/run/ntpd.pid | | # cat /proc/2252/status | Name: ntpd | ... | Uid: 38 38 38 38 | Gid: 38 38 38 38 | FDSize: 32 | Groups: 0 1 2 3 4 6 10 But it has still the supplementary group ids. Version-Release number of selected component (if applicable): ntp-4.2.0.a.20040616-2