Re: tlug: Once again sendmail problem/solution

["Stephen J. Turnbull" <turnbull@example.com>]

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tlug note from "Stephen J. Turnbull" <turnbull@example.com>
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>>>>> "Dennis" == Dennis McMurchy <denismcm@example.com> writes:

    Dennis>   A while back I reported a new problem with the sendmail
    Dennis> MTA on my system.  After long faithful service it had
    Dennis> developed the nasty habit of sometimes just getting stuck
    Dennis> with a open connection to another mailserver.

    Dennis> But it would just remain stuck there for unacceptably long
    Dennis> periods.  This seemed to happen mostly with ac.jp domains,
    Dennis> but not exclusively.

Probably what is happening, then, is that the MTA on the other end is
timing out and not telling you about it.  Presumably you could set
your sendmail timeouts shorter.  (But don't, see below.)
Communication between the ac.jp domain and the rest of Japan is
unacceptably slow, period.  The main nerve center in Tokyo seems to be
engineered about as well as the Shuto expressway; ie, it bears a
strong resemblance to a gangrenous cancer, but none at all to MAE East
or West.  (I could be wrong, and this may be only a problem for SINET,
but I suspect it's more widespread, since Craig's FTP host of choice
is KDD, not SPIN or IIJ or whatever.  KDD is on IMNet==Inter-Ministry
Research Information Exchange Network, which is the Japanese
equivalent of the original ARPAnet, I believe---it has good
connections to everything, anyway.)

There's no excuse for this, because for downloads I often get equally
good performance from remote hosts in Kyoto, Osaka or Sendai, and our
local Sun workstation (which is admittedly *very* heavily loaded), as
long as the remote host is an ac.jp host.  The fumbles in Tokyo seem
to be inter-origanizational coordination problems.

    Dennis>   Finally one of the engineers at gol.com suggested
    Dennis> defining a relay host (e.g. relay.gol.com), because my
[ snip ]

    Dennis>   I haven't tested it a lot, but the piece that was stuck
    Dennis> in the mail queue earlier has now gone out without any
    Dennis> fuss.

This is a *good* idea, unless you have a strong reason (eg, you are
doing obnoxious bulk mail via promiscuous relays) to conceal your
domain of origin, or you distrust your relay host (I don't relay
things because shako.sk.tsukuba.ac.jp goes down a lot more than
turnbull.sk.tsukuba.ac.jp does :-( ), or you're always in a tearing
hurry to get things delivered (relay hosts tend to be high volume, so
they can get high efficiencies by batching transmissions to the same
host together every hour or few hours).

The advantages:

(1) Minimize transmission time.  relay.gol.com is going to be the
    fastest host you can connect to, no?
(2) No waits for retries of unavailable hosts, or retransmissions of
    fumbled connections.
(3) The relay host will be optimized for mail, and may in fact know
    better routes for the mail than your machine does.  (On the
    Internet, minimum distance is not always minimum hops.)
(4) GOL knows mail better than you do.  If there are problems, they'll 
    take care of it.  (If either of those isn't true, find a new
    provider---and let me know, I'm a customer too!)  So let them....

There may be other advantages too.

Steve

-- 
                            Stephen J. Turnbull
Institute of Policy and Planning Sciences                    Yaseppochi-Gumi
University of Tsukuba                      http://turnbull.sk.tsukuba.ac.jp/
Tel: +81 (298) 53-5091;  Fax: 55-3849              turnbull@example.com
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