[comp.mail.misc] weird sendmail diagnostic

jc@minya.UUCP (John Chambers) (02/04/88)

In article <127@faraday.sunysb.edu>, rosalia@faraday.sunysb.edu (Mark Galassi) writes:
> 
> Here is a copy of a "mqueue" temp file (part):
> 
>    ----- Transcript of session follows -----
> >>> HELO marconi.sunysb.edu
> <<< 553 marconi.sunysb.edu I refuse to talk to myself
> 554 <MAILER-DAEMON@marconi>... Service unavailable: Bad file number
> 
By some coincidence, just this happened to me a few weeks ago, putting
our department email gateway down for most of a week until Chuq van Rospach
suggested the solution: a reboot.  It went away.  [No promises that it'll
solve your problem, though. :-]

It seems that we had installed a new /etc/hosts file from the central
source on another machine, and they had slightly modified the line for
our machine.  The BSD kernel does something clever with this line, and
if the kernel's version and the one in /etc/hosts don't agree, all sorts
of things start getting weird.  One of the symptoms is sendmail saying
that it refuses to talk to itself.  It was doing this on all incoming
mail from anywhere.

I'm not sure whether this is a bug or a feature, but I've taken steps
to ensure that it doesn't bite me again.  I have a secret copy of my
machine's /etc/hosts entry, and any time /etc/hosts gets changed, I
have code lurking that hunts down the local host's entry, deletes it,
and replaces it with the secret entry.  Drastic, but at least that's
one weirdness that won't arise here again.  

-- 
John Chambers <{adelie,ima,maynard,mit-eddie}!minya!{jc,root}> (617/484-6393)