[CentOS] System Start-Up Issue Progress

Tue Jul 4 21:17:23 UTC 2017
Chris Olson <chris_e_olson at yahoo.com>

Organization policy dictates that information copied from systems
with Internet access be "sanitized".  Thus the FAKE name computer
as well as the designations nnnn and mmmm provided in my previous
messages and presented again below:

computer sendmail[nnnn]: unable to qualify my own domain name (computer)

computer sendmail[mmmm]: My unqualified host name (computer) unknown;
sleeping for retry

The actual system has totally legitimate names for domain and host.

What actually happened during the system update is still being
investigated.  In the three years that this virtual CentOS 6
system has been running, updates have taken us from 6.5 to 6.9.

These updates have been executed using yum update and accepting
all updates available.  This is the very first time anything like
this has happened. All updates have been successful.  It is very
fortunate that we do not need sendmail.

Thanks again for responses to my messages. We are still learning.

    On Tuesday, July 4, 2017 1:42 PM, Alexander Dalloz <ad+lists at uni-x.org> wrote:

 Am 04.07.2017 um 19:13 schrieb Gordon Messmer:
> On 07/04/2017 09:21 AM, Chris Olson wrote:
>> It remains a mystery what could have happened during a standard yum
>> update of the system to cause this domain and/or host related sendmail
>> issue.
> Run "hostname".  Has the hostname changed?  Run "ls -l /etc/hosts 
> /etc/resolv.conf".  Have those files changed recently?
> It's possible that this system was working in the past because its 
> hostname was set up in DNS, and was removed.  In that case, the problem 
> wasn't related to "yum."  sendmail would (IIRC) continue working after 
> the system's hostname was removed from DNS, until the next time the 
> system rebooted.

Sendmail demands a hostname with at least a single dot in it. "computer" 
is in no way a valid FQDN. "computer.localdomain" would be fine and if 
it has an entry in /etc/hosts.


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