[ntp:questions] Three NTP servers, one strange IP-address in 'refid'

Sander Smeenk ssmeenk at freshdot.net
Mon Mar 31 15:32:56 UTC 2014


I'm running four NTP-servers. One has a PPS and is stratum-1, the other
three sync from that one primarily and have a few out-of-band fallback
servers configured. This seems to work fine.

However, if i check 'ntpq -c lpeers' on one of the three stratum-2
servers i see an IP-address listed as 'refid' for the 'peer'-entries
in my configuration. This IP-address is not used in any of my
configurations, no traffic is flowing to- or from that IP either.

Could someone explain me where this IP comes from:

| root at dns1:~# ntpq -c lpeers
|      remote           refid
| ===============================
| *someserver.tld  .PPS.
| +someserver2.tld .GPS.
| -someserver3.tld .PPS.
|  dns2.dns.dmz.bi
|  dns3.dns.dmz.bi
| +someserver4.tld .PPS.

Evidently, on dns2 it shows dns1 and dns3 with the same IP.
And on dns3 it shows dns1 and dns2 with the same IP.

Config on the three servers is:

| driftfile /var/lib/ntp/ntp.drift
| disable monitor
| restrict default nomodify noquery notrap nopeer
| restrict -6 default nomodify noquery notrap nopeer
| restrict :: nomodify noquery notrap nopeer
| restrict
| restrict ::1
| # Servers
| server someserver.tld prefer
| restrict someserver.tld nomodify
| server someserver2.tld
| restrict someserver2.tld nomodify
| server someserver3.tld
| restrict ntp3.tdc.fi nomodify
| # peers
| peer
| restrict
| #peer
| #restrict
| peer
| restrict
| peer
| restrict

The peer-set is changed between the three ntp servers so they dont use
themselves as peers. Other than that configuration is identical between
the three servers.

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