Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!julius.cs.uiuc.edu!ux1.cso.uiuc.edu!mp.cs.niu.edu!rickert
From: rickert@mp.cs.niu.edu (Neil Rickert)
Newsgroups: comp.mail.sendmail
Subject: Re: $=m class
Message-ID: <1990Sep26.220824.19155@mp.cs.niu.edu>
Date: 26 Sep 90 22:08:24 GMT
References: <9629@ur-cc.UUCP>
Organization: Northern Illinois University
Lines: 52

In article <9629@ur-cc.UUCP> Mark Sirota <msir@cc.rochester.edu> writes:
>According to the SunOS 4.1 System & Network Administration manual, page 746,
>the $=m class is a special class set to the domain name of this host.
>
>Well, pardon me if I'm wrong, but isn't the domain name a singular value?
>Shouldn't it therefore be a macro, not a class?  How is this class created,

  Since this seems to work on Sun's, I guess it is ok for it to be a class.
Presumably Sun has installed some special purpose code in their versions of
sendmail to handle this.  Normally a class can only match a single token,
so this must be specially handled.  In other words it does not work like a
normal class.

>While I'm at it, I have a second question regarding hostnames.  The $w macro
>is set to the hostname of this site.  For some sendmails, this is always the
>short name, even if the hostname as reported by gethostbyname() contains the
>domain.  For other sendmails, the entire hostname is stored.  This is an
>annoying discrepancy between various sendmails...

  Older versions of sendmail set this to the hostname as reported by
gethostname() - not gethostbyname().  Versions which are designed to read
MX records from a name server set it to gethostbyname(gethostname()) - please
excuse the wrong argument types - so that it will be fully qualified.
When there are MX records, sendmail needs to be able to tell whether the
MX record is to the local host, so there is a comparison with the value
of $w, and this will only work correctly if $w is fully qualified.

  IMHO they should have done the comparison with $j, which would have
caused less trouble.  But presumably the programmers at Berkeley decided
that $w is more reliable since it is defined internally and $j is not.  I
think this was a mistake since the defined meaning of $j is more precise
than the defined meaning of $w.  (On the other hand an awful lot of systems
have $j wrongly defined - but then the same systems probably have $w wrongly
defined too).

>In any case, the $=w class is supposed to be a special class set to all of
>the names this host is known by.  Where does this information come from, and
>for newer sendmails for which class tokens can contain dots, does this
>include the domain name or not?  The same question abotu a debugging value
>applies as above...

 This is defined in code.  I haven't tested it, but it probably doesn't work
properly with MX versions where the hostname contains periods.  Get the
IDA versions of sendmail which allow $=x matches to work with multi-token
comparisons.  The '$=w' definitely works there.  However to match all names
of the host you will still need some 'Cw' lines in sendmail.cf.  They have
not yet fully implemented the RPM instruction (Read the Programmer's Mind).
-- 
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
  Neil W. Rickert, Computer Science               <rickert@cs.niu.edu>
  Northern Illinois Univ.
  DeKalb, IL 60115.                                  +1-815-753-6940