[ntp:questions] Source address in response not the same as target address in request

Phil_Newlon at wendys.com Phil_Newlon at wendys.com
Thu Aug 28 19:34:44 UTC 2008


I have NTP server running on two Red Hat boxes.  Each box has a primary
address on eth0, and share a virtual IP address that is managed by linux-ha
heartbeat.

NTP requests sent to the virtual IP address are responded to by the primary
address of eth0 on the server that is handling requests at the time.  Thus,
if I execute an "ntpdate -q 10.0.0.1" where 10.0.0.1 is the virtual IP of
eth0:0 and 10.0.0.2 is the IP of eth0, the response is sourced from
10.0.0.2.  Thus, the ntpdate query fails with the message "no server
suitable for synchronization found".

I found this thread
http://lists.ntp.isc.org/pipermail/questions/2007-December/016262.html that
touches on the subject.

I found another thread that states:

pick up a version 4.2.4p2 or above:
...
ntpd will ALWAYS bind to all interface addresses but each interface address
can be Enabled or Disabled. Enable means packets will be received and
processed
by the packet reception logic. Disable means that these packets are dropped
right away

I am running ntpd 4.2.0a which is the version that comes with RHEL 4 Update
6.

So, if I read this correctly, I should be able to upgrade to 4.2.4x and
configure NTP to not bind to eth0, so it will receive and respond to
requests only on the virtual interface eth0:0?

Thanks!

Phil




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