Hi, I think you have misunderstood the hostname command. It appears the problem you are facing is due to your domain name not set properly.

There are 2 parts to a name: hostname, domainname.

The hostname command shows the hostname part, unless you call it with the -f switch.

This is how `hostname` was intended to work on a host that is known on the internet as "foo.bar.com":

# hostname foo # hostname -s foo # hostname -f foo.bar.com # hostname -d bar.com

(Please look at hostname --help for more details about the switches).

In your original configuration, your hostname was set to "foo" and you did not set a domain. When courier talks to other smtps, it combines "foo" with blank and ends with FQDN being "foo", thus the error 550.

After you set the hostname as "foo.bar.com", courier still combine that with blank, but ends up with "foo.bar.com", which is accepted while talking to other smtp. This solves the problem for courier. Seems like 2 wrongs make 1 right.

Maybe you want to review your /etc/hosts to implement the proper domain instead:

127.0.0.1 localhost [machine ip addr] foo.bar.com foo

NOTE: the order of the names for your ip address is important. The first name to an ip address is taken to be the FQDN for the machine.

Regards, Leon