Do you think it might have something to do with your DHCP lease expiring?
-----Original Message----- From: owner-scientific-linux-us...@listserv.fnal.gov [mailto:owner-scientific-linux-us...@listserv.fnal.gov] On Behalf Of Dan Sent: Friday, August 18, 2017 6:54 AM To: scientific-linux-users@fnal.gov Subject: Regular loss of DNS name resolution on SL7.3 machine ** EXTERNAL ** 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. 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.) The regular nature of the failures led me to take a look in /var/log/cron. There seems to be a bit of a pattern that, a few minutes before a failure, /var/log/cron contains entries pertaining to the following executables: /usr/lib64/sa/sa1 /usr/libexec/pcp/bin/pmlogger_check /usr/libexec/pcp/bin/pmie_check Does anyone have any idea what's going on, please? Kind regards, Dan *** This email is from an EXTERNAL sender *** Use caution before responding. DO NOT open attachments or click links from unknown senders or unexpected email. If this email appears to be sent from a Platte River Power Authority employee or department, verify its authenticity before acting or responding. Contact the IT Help Desk with any questions.
