http://forum.linuxcareer.com/threads/1697-Sendmail-quot-unqualified-hostname-unknown-sleeping-for-retry-unqualified-hostname

Sendmail: "unqualified hostname unknown; sleeping for retry unqualified hostname

Description:

Sendmail hang or is very slow when sending an email.

Code:

debian sm-mta[8129]: My unqualified host name (debian) unknown; sleeping for retry

Operating System:

Linux

Solution:

sendmail is searching for a FQDN ( fully qualified domain name ). In our case the host name is "debian" and that is not a FQDN. To resolve this problem change /etc/hosts:

FROM:

Code:

127.0.0.1 localhost

127.0.1.1 debian

TO

Code:

127.0.0.1 localhost.localdomain localhost debian

127.0.1.1 debian

Where "debian" is a hostname.