On Fri, 18 Aug 2017, Dan wrote:
Dear All,
I wonder if anyone can help with the following strange network problem
I'm having on my SL7.3 machine, please:
Every day, just after midday, I suddenly lose access to DNS name
resolution, and therefore become unable to interact with any remote
hosts, even though my network interface is still up. Manually taking
the network interface down then up again restores name resolution
(although bringing the interface back up is surprisingly slow), but
only for a few minutes before it fails again. These cycles go on
until about 1pm, after which all is fine once more.
This could be a red herring, so beware of wild goose chases.
You appear to be on timezone +0100 (from other header info I'm
going to assume BST). I've seen software break for just that one hour
when there has been a confusion over BST/GMT.
(IIRC the reason was that the date/time was rounded to the nearest day
by adding 12hrs and truncating.)
If I try to ping the nameserver (by IP address) during one of the
periods of name resolution failure, I'm met with ICMP "destination
unreachable" packets originating from my own IP address on the
relevant interface. (Whereas pinging the nameserver at any other time
produces successful responses.)
Does ping -n have the same problem ?
