[TriLUG] ntpd misbehaving

[Michael Hrivnak]

I run ntpd on a Mandriva machine in my home and sync the rest of my machines 
to it.  It keeps very good time, and according to ntpq, the offsets and 
jitters relative to higher-stratum machines are quite low.

Then there's my desktop machine which has serious problems keeping time.  It 
runs ntpd configured as so:

/*------------------
#/etc/ntp.conf
server 192.168.12.1 prefer maxpoll 7
driftfile /etc/ntp/drift
multicastclient                 # listen on default 224.0.1.1
broadcastdelay  0.008
-------------------*/

The clock tends to rapidly gain time.  24 hours after manually syncing the 
time (ntpdate 192.168.12.1) and then starting ntpd, here's where it sat:

/*----------------
# ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 192.168.12.1    128.2.181.91     3 u   21  128  377    0.261  -101968 1243.16
--------------------*/

Apparently it's exceeding the maximum tolerable drift value, as seen here in 
the logs:

/*----------------
# zgrep ntpd /var/log/syslog.*
syslog.5.gz:Nov 20 02:03:54 localhost ntpd[3844]: synchronized to 
192.168.12.1, stratum=3
syslog.5.gz:Nov 20 02:08:11 localhost ntpd[3844]: frequency error -512 PPM 
exceeds tolerance 500 PPM
syslog.5.gz:Nov 20 02:12:29 localhost ntpd[3844]: time reset -1.441427 s
syslog.5.gz:Nov 20 02:12:29 localhost ntpd[3844]: frequency error -512 PPM 
exceeds tolerance 500 PPM
syslog.5.gz:Nov 20 02:22:09 localhost ntpd[3844]: synchronized to 
192.168.12.1, stratum=3
syslog.5.gz:Nov 20 02:22:09 localhost ntpd[3844]: frequency error -512 PPM 
exceeds tolerance 500 PPM
syslog.5.gz:Nov 20 02:29:37 localhost ntpd[3844]: time reset -1.529274 s
syslog.5.gz:Nov 20 02:29:37 localhost ntpd[3844]: frequency error -512 PPM 
exceeds tolerance 500 PPM
----------------*/

There are several questions here.  Foremost, what can I do to keep better 
time?  Other questions are: What exactly is "jitter"? I can't even find what 
it's units are.  My understanding is that the frequency error is in 
milliseconds, but what does PPM stand for?  Why won't it tolerate a greater 
frequency error?

Thanks!

Michael