[Mailman-Users] fully qualified domain name

[Paolo M. Pumilia]

Received from Paolo M. Pumilia, On Wed Oct 20 at 20:31:
 .
 .Mail sent to user1 from another user on the same host are promptly received
 .whether using the address  user1  or  user1 at dom.org   or  user1 at hname.dom.org
 .
What i would like to figure out is how did the host name 'hname' enter the address. 
I have always used 'user1 at dom.org' in configuration files (alias, ect.); 
I wonder where, in the python routines (i guess), the address has been changed to the 
fully qualified domain name.
Any help?

thank you
Paolo Pumilia
email: pumilia at est.it
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