Hi Alpha managers,
This was my original question:
------------------------------
We have an AXP host (OSF/1 3.0) at our site which apart from another application
serves as our central mail host, communicating directly over a leased line
with our Internet supplier.
Mail is exchanged with a Microsoft Mail SMTP gateway (a DOS PC) via the local
area network. We have no problems receiving and sending mail directly on the AXP
host, but incoming mail routed to the SMTP gateway stalls on the AXP from time
to time.
The "mailq" command shows a lot of mail files waiting to be transferred with
the error messages "Deferred: Connection refused by the SMTP gateway".
The "ping" command shows that the SMTP gateway is alive and the "nslookup"
command also verifies that the gateway is known by the name server.
We believe this to be a problem rather on the SMTP gateway than on the AXP.
Does anyone who has the same kind of setup recognize these problems and know
what we could do to trace the problem? Rebooting the SMTP gateway does actually
help for a few hours until it decides to stop receiving mail again, but this is
not practical in the long run.
------------------------------
I received the following hints:
1) Once I encountered the same problem with a Axp and a Novell Server =
running Mercury as an SMTP Gateway. Novell was complaining about not =
accessing to the Axp server. here was a bridge between the Novell and =
the Axp Server and when I reset the bridge, everything started to work. =
The bridge was the source of the problem. Hope this helps.
-----------
2) First, the MS SMTP gateway dos software has patches, available from
ftp.microsoft.com, we've downloaded and it hangs infrequently now (less than
once a week).
Secondly, try other NT based solution, such as Mailnet, Postoffice,
Netconnex (but we have problem starting Netconnex and I don't have time to
look at it again).
-----------
3) You've hit it on the head: the MS SMTP gateway is not very stable. Some
things you can do are:
a) ensure that only the AXP system is the only one connecting
to the SMTP g/w: i.e., set up MX records for the SMTP g/w
pointing to the AXP. This should clear up at least 90% of the
hangs.
b) restart the SMTP g/w periodically, like once an hour. I use
a batch file like this:
set TZ=EST5EDT
smtpgate -ci -gacsy -br1:00
choice /c:ynr /n /t:n,5 Exit to DOS [Y,N,Reboot]?
if errlevel 3 warmboot
if errlevel 2 goto MCheck
if errlevel 1 goto End
:MCheck
net use m:
if errorlevel 1 coldboot
goto TOP
:End
c) make sure you have the latest SMTP g/w software. You can
check ftp.microsoft.com or search the MS Knowledgebase at
http://www.microsoft.com/
-----------
4) Tried doing 'telnet <gateway's name> 25' to see if anybody's listening?
-----------
5) As I said to someone a while ago on this list - Microsoft's SMTP gateway is
braindead. We get this message also but less frequently now that we have
moved the unix end of it to a different machine (now linux which is the DNS,
mail and news server, was a sun which was running lots of other things).
On our system though, the gateway didn't need to be rebooted, the messages
would go through when sendmail tried the next time. At one point it was
happening so frequently that I would manually issue the command 'sendmail
-q' to force sendmail to push the messages through then. This worked fine.
As I said the problem has mostly disappeared now.
------------
6) The exact same thing happens on my setup: I have an Alpha 2000 as my
sendmail server, and a Microsoft SMTP gateway . I constantly have mail queued
up as well on the Unix side waiting to get sucked into MSMAIL.
The best answer about the problem that I have found is this: the DOS SMTP
gateway is single-threaded, so if multiple messages try to get dumped to it by
your Unix box, it will only accept one. This means you'll get a message like
the following:
Connection Deferred: waiting during timeout with <SMTP gateway>
or, connection refused by <smtp gateway> during wait with.
So far I have found 4 (i think) messages from Sendmail that more or less mean
the same thing: the MS gateway refused the connection because it was either
a) already processing an SMTP to MSMAIL mail transfer
b) transmitting from MSMAIL to SMTP
c) it just didnt want to (maddening, isnt it!)
Depending on the size of the message, and (it seems) by the number of MSMAIL
recipients the message is addressed to, your buildup in mailq will sometimes be
really long, and other times instantaneous. Make sure you don't have any MSMAIL
building up in your PC queue, either. (check with Admin.exe under queue,
(CTRL-ENTER) then (ENTER) , select the SMTP queue and check the contents)
Before I got you mail tonight I had been planning on asking a similar question:
How can I tell Sendmail to deliver the queue contents faster, or now, or
something!
-------------
To make it short we haven't really solved the problem completely. However,
suggestion 6) gives some good clues as to what actually goes wrong. We ended
up using suggestion 3) which is a good work-around. Restarting the gateway
periodically does have a good effect (but it shouldn't really be necessary if
the gateway is working properly). We had already installed the patches
mentioned above, too.
Our situation now is that the mail queue still stalls, but it doesn't get
so long as before. We could have up to 50 mails waiting to be transferred
until it pleased the gateway to receive them - now we usually don't have more
than 10 waiting.
The conclusing is: Microsoft's SMTP gateway has to be improved, but you can
get an acceptable functionality by making the above mentioned work-around.
Thanks to the following for their helpful hints:
Suleyman Nazif Kutlu, Turkey
James Soh, USA
Harold March, Canada
Boris, USA
Dave Thomson, New Zealand
Jean-Loup Risler, France
Best regards
Paul Hostrup-Jessen
Department of Electronic Data Processing
Unix system administration
Bruel & Kjaer A/S
DK-2850 Naerum
DENMARK
email: phjessen_at_bk.dk
tel. : +45 45 80 78 55 + 2433 (direct dial from touch-tone telephones)
fax : +45 42 80 14 05
Received on Sat Jan 13 1996 - 15:05:30 NZDT