On 4/10/19 8:23 AM, Simon Matter via CentOS wrote: >> Hi, >> >> For the last ten years or so, I've defined the short hostname in >> /etc/hostname and the FQDN in /etc/hosts. Now I wanted to double-check >> this information, which eventually led me to this page: >> >> * >> https://serverfault.com/questions/331936/setting-the-hostname-fqdn-or-short-name >> >> Now I admit I'm even more confused than before. >> >> Is there some reliable piece of information on this subject for CentOS ? > > IMHO for those having proper DNS in place, the hostname should be set to > the FQDN in whatever place it is supposed to be set. I quite feel there is > something wrong if the only place where the FQDN is listed is the > /etc/hosts file. > > I'm not very happy with how the issue was handled in Linux and the > different distributions in the last decades. Not to mention the > inconsistency in the relevant man pages. Well, I am unhappy for about as long about /etc/hosts and how name resolution "should" happen which it doesn't, namely, if /etc/nsswitch.conf says hosts: files dns then ideally /etc/hosts should be used first, then nameservers. However (and this is true both for Linux and FreeBSD), some commands never look into /etc/hosts (e.g., command host), whereas some do use /etc/hosts (e.g., command ping). Valeri > > I found the info mentioned in the FreeBSD man pages quite helpful even if > it has to be "translated" to Linux. See the excerpt of the mentioned man > pages below. If you believe this is heresy to be posted here, please don't > read it :-) > > Regards, > Simon > > ----%>------------------------------- > root at freebsd:~ # man hostname > HOSTNAME(1) FreeBSD General Commands Manual > HOSTNAME(1) > > NAME > hostname - set or print name of current host system > > SYNOPSIS > hostname [-f] [-s | -d] [name-of-host] > > DESCRIPTION > The hostname utility prints the name of the current host. The > super-user > can set the hostname by supplying an argument; this is usually done in > the initialization script /etc/rc.d/hostname, normally run at boot time. > This script uses the hostname variable in /etc/rc.conf. > ... > > > root at freebsd:~ # man rc.conf > RC.CONF(5) FreeBSD File Formats Manual > RC.CONF(5) > > NAME > rc.conf - system configuration information > > DESCRIPTION > The file rc.conf contains descriptive information about the local host > ... > hostname (str) The fully qualified domain name (FQDN) of this host on > the network. This should almost certainly be set to > something meaningful, even if there is no network connection. > If dhclient(8) is used to set the hostname via DHCP, this > variable should be set to an empty string. Within a jail(8) > the hostname is generally already set and this variable may > absent. If this value remains unset when the system is done > booting your console login will display the default hostname > of "Amnesiac". > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos > -- ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++