On Mon, Mar 7, 2011 at 11:34 AM, Sean Carolan <scarolan at gmail.com> wrote: > Can anyone point out reasons why it might be a bad idea to put this > sort of line in your /etc/hosts file, eg, pointing the FQDN at the > loopback address? > > 127.0.0.1 hostname.domain.com hostname localhost localhost.localdomain > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > It's common to do so, so that the network lookups for "hostname" still operate, even if the rest of the network is dead. This is particularly important for self-monitoring, sendmail (which relies on the FQHN beinf first, mind you!!!) and X Windows. If you have an intermittent network connection, such as one for a DSL connected device or a roving wireless connection, keeping the hostname in the 127.0.0.1 line helps assure that the X sessions work, even when other connections are interrupted. It also helps improve performance for local network access and keeps your external ports uncluttered by local CIFS and NFS access. That said, it can be problematic when you "ping $HOSTNAME" and get a valid 127.0.0.1 response, and haven't actually tested your external port. It also requires thought for configuring SSH and SNMP and NFS to allow localhost access.