strange cyradm behavior

[uno]

Could sombody please explain this?

If I do:
cyradm -u cyrus localhost

I get prompted for "IMAP password:"
I then type the password once entered from the standard passwd command 
and I am in
and can create mailboxes.


If I do:
cyradm -u cyrus myhost.mydomain.net
I get the prompt "password"
Then I fill in the password set by standard unix password and get
a new prompt. This time for The IMAP password. If I enter the same
password again cyradm fails on line 118 of Admin.pm


The host myhost.mydomain.net is in /etc/hosts, just like localhost and 
both end up at the same host
just different network addresses (127.0.0.1 and 192.168.0.19). I can 
ping the host using both names,
and files is set to take precedence over dns in my /etc/nsswitch.conf

It seams to me tha different auhentication mechanisms are at play here.

MECH in /etc/sysconfig/saslauth is set to pam.

So why do I get different prompts and why is authentication successful 
if I use localhost?


Regards
Uno Engborg