[sf-lug] interesting artifact re system mail configuration

[jim]

   i've complained and asked various smart people 
for help. one smart person, daniel mizyrycki, 
figured out the problem, 

   i'm using ubuntu server 8.10 and postfix 
(whichever release ubuntu includes) as MTA, and 
for MUA i'm using good ol' mail (not recommended 
as it doesn't allow multi-line editing: i've got 
to be sure the current line is right before i 
hit the Enter key). 
   the problem was that outbound mail had in the 
From: field not only user at domain in angle 
brackets but the hostname prepended as the 
common name: sill <jim at systemateka.com> 
   how to get rid of that "sill"? i looked 
through postfix config files and docs till i 
was blind. i looked through mail config and 
doc files similarly. i discovered that there's 
such a thing as an MSA (mail sumission agent, 
an interesting possibility in itself), and i 
discovered that it's difficult to find docs 
that describe the overall architecture of the 
system with respect to mail--what are the MUA, 
MSA, MTA relationships in the shipping release? 

   the mail client picked up the hostname from 
the comment field in /etc/passwd for the 
current user. why i'd put the hostname (sill) 
there escapes me, but i did. 
   the exact contents of the comment field were 
:sill,,,: 
so i changed them to 
:james stockford,,,: 
and what do you know, sending mail now 
populated the common name with james stockford. 
   i then put a comma character as the first 
character in the comment field 
:,james stockford,,,: 
and sending mail populated the From: field with 
nothing, and jim at systemateka.com was no longer 
in angle brackets. 

   i know this is pretty arcane, but it may be 
useful for those setting up systems to know 
that at least the mail client references the 
comment field in /etc/passwd and it strikes 
me as interesting that daniel would have 
figured it out.