BIND: Clocks are Unsynchronized Error and Solution

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Q. I’ve configured BIND named TSIG as documented here. It worked for some time, but my /var/log/messages got the errors as follows:

zone example.org/IN: refresh: failure trying master 71.22.11.22#53 (source 0.0.0.0#0): clocks are unsynchronized: 9 Time(s)
zone example.org/IN: refresh: failure trying master 71.22.11.22#53 (source 71.22.11.22#0): clocks are unsynchronized: 9 Time(s)

How do I fix these errors under Debian Linux 64 bit etch server?

A. BIND and many other UNIX / Linux / BSD services depends upon accurate timings. You need to use the Network Time Protocol (NTP), which is a protocol for synchronizing the clocks of computer systems over packet-switched, variable-latency data networks. NTP uses UDP port 123 as its transport layer. It is designed particularly to resist the effects of variable latency by using a jitter buffer. Under Linux / UNIX you can use ntpd or openntpd software implementation to sync clock.

To install ntpd under Debian, enter:
# apt-get update
# apt-get install ntp

You need ntp installed and configured on both master and slave DNS server. Once installed it will automatically sync clock using server specified in /etc/ntp.conf file:
server 0.debian.pool.ntp.org iburst
server 1.debian.pool.ntp.org iburst
server 2.debian.pool.ntp.org iburst
server 3.debian.pool.ntp.org iburst

Once ntpd started bind should work without a problem. Reload named to push pending updates:
# bind reload

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

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3 comment

  1. About the above info you have as i listed below:
    To install ntpd under Debian, enter:
    # apt-get update
    # apt-get install ntp
    My question “where do you enter the data?” in the run command?
    You should mention this as it confuses new guys.

  2. where do you enter this?
    To install ntpd under Debian, enter:
    # apt-get update
    # apt-get install ntp

    in the run command?

  3. You need to type apt-get commands at a shell prompt. Open terminal and type the commands at bash shell prompt.

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