I've recently upgraded my PC to Ubuntu 16.04 from Ubuntu 11.04. What I used to do was go into /etc/ntp.conf and add the specific server that I wanted to use as a source. For example:
server 192.168.1.250 true prefer iburst
However since the upgrade I have found that trying to add any "server ipaddr" to /etc/ntp.conf makes ntp stop running. I can do "server name.of.server", but if it is an actual ip address ntp seems to refuse to run. When I look at "systemctl status ntp" it says it is fine and active. But when I look at "ps aux | grep ntp" it is not running. I also tend to believe it isn't actually running because I have another PC that uses this one as the ntp source and it is unable to get the time when this PC is in this state.
In /var/log/syslog I see:
ntp: * Starting NTP server ntpd ntp: ...done. ntpd: ntpd email@example.com Wed Jul 12 12:24:46 UTC 2017 (1): Starting ntpd: Command line: /usr/sbin/ntpd -p /var/run/ntpd.pid -g -u 113:120 ntpd: proto: precision = 0.277 usec (-22) ntpd: proto: precision = 0.277 usec (-22) kernel: [ 15.723943] audit_printk_skb: 12 callbacks suppressed kernel: [ 15.723946] audit: type=1400 audit(1554557240.012:16): apparmor="DENIED" operation="mknod" profile="/usr/sbin/ntpd" name="/var/log/ntpd.log" pid=1119 comm="ntpd" requested_mask="c" denied_mask="c" fsuid=0 ouid=0 ntpd: restrict 0.0.0.0: KOD does nothing without LIMITED. ntpd: restrict ::: KOD does nothing without LIMITED. ntpd: unable to bind to wildcard address :: - another process may be running - EXITING
I don't understand why adding a server with an IP to /etc/ntp.conf is causing problems and I haven't been able to find anything in my searches. I saw that Ubuntu 16.04 wants to use timesyncd instead of ntp, but it seems that you should still be able to use ntp.
Does anyone have information about why this might not be working? Do you have any recommendations on how to further debug this issue? Thank you in advance for your help.