[ On Saturday, July 5, 2003 at 10:03:23 (-0700), Jim Pazarena wrote: ]
> Subject: [Exim] broken MTAs
>
> I see a *lot* of traffic in this newsgroup refering to:
>
> "some broken MTAs"
>
> which MTAs are broken? Can anyone name 2 ? (excluding anything
> produced my Micr$so$t).
What do _you_ mean by "broken"? :-)
Or rather what kinds of breakage are you interested in knowing about?
I think every MTA has its quirks.
Lots of MTAs are like Exim and assume the person configuring and
operating them has at least half a clue about what they're doing and so
if that's not true then a lot of breakage can show through. Some, like
Postfix, have at least minimal sanity checking of their configurations,
though often they require running a separate command ("postfix check")
to catch all the warnings and only the most critical problems will
prevent them from operating. Postfix, for example, will happily use the
unqualified $myhostname value as the $mydomain value if it can't figure
out the default domain by any other means and of course this results in
mail being sent with FQDNs like "<root@???>". :-)
I would say the worst kinds of errors are those where the mailer doesn't
deal with errors very well. For example lots of mailers, and especially
those that are only client-SMTP systems (i.e. MUAs that use SMTP as a
message submission protocol) don't report the first error returned to
them, and many only report either the first or last line of error
responses when they do report any SMTP error). Some ignore 5xx errors
and keep retrying. Some don't properly handle errors after HELO/EHLO or
after MAIL FROM: or after the end-of-DATA (".") command. Many don't
honour required retry delays. Etc., etc., etc.
--
Greg A. Woods
+1 416 218-0098; <g.a.woods@???>; <woods@???>
Planix, Inc. <woods@???>; VE3TCP; Secrets of the Weird <woods@???>
