A big message overwhelmed MailScanner

[Alex Neuman van der Hans]

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Take the user out back and beat them with a clue stick.

I had a client that specifically asked me *not* to put any size 
restrictions on his e-mail whatsoever. One day, a user decided to send 
her entire Outlook file (almost 2gb) to another user; she said she 
needed that other user to have a copy of all her e-mail and contacts, 
etc.  The server started to choke; even so, she managed to send *another 
copy* of her PST file since it had been "more than 5 minutes since she 
sent the first one and it hadn't arrived". She was used to the 
near-instantaneous response time provided by a finely tuned server.

Needless to say, caps were put at the MTA level (50MB) and at the 
individual user level using rulesets. My experience is that you should, 
at least for the sake of your server's health - not to mention bandwidth 
- limit your message sizes to something less than half the RAM 
available. Any message with attachments over 100MB in size means your 
users are in desperate need of a more reliable file transfer solution, 
such as (s)ftp. Even corporate intranets using php to upload files are 
prone to this, that's why PHP usually defaults to 8M max uploads.


Kai Wang wrote:
> Hi,
>
> We are running MailScanner 4.43.8. Our message size limit is 50M. I 
> noticed a valid message was stuck in MailScanner for over an hour. The 
> server's load was very high and email processing was very slow. 
> Eventually I had to move it to the delivery queue manually. Does 
> anybody know what's the best practice for this situation?
>
> -rw-------    1 root     root     48384095 Oct  4 09:57 dfj94FuH024035
> -rw-------    1 root     root          867 Oct  4 09:57 qfj94FuH024035
>
> Oct  4 09:57:20 smtp1 pc214-161.psych.ucalgary.ca [136.159.214.161]: 
> DATA[24035]: j94FuH024035: from=<XXXXXX at ucalgary.ca>, size=48384415, 
> class=0, nrcpts=1, 
> msgid=<a2a2d24bbef12aafca57ff41575a2abe at ucalgary.ca>, proto=ESMTP, 
> daemon=MTA, mech=PLAIN, relay=pc214-161.psych.ucalgary.ca 
> [136.159.214.161]
> Oct  4 09:57:20 smtp1 pc214-161.psych.ucalgary.ca [136.159.214.161]: 
> DATA[24035]: j94FuH024035: to=<XXXXXX at ucalgary.ca>, delay=00:01:03, 
> mailer=relay, pri=48414415, stat=queued
> Oct  4 09:57:21 smtp1 pc214-161.psych.ucalgary.ca [136.159.214.161]: 
> DATA[24035]: NOQUEUE: --> 250 2.0.0 j94FuH024035 Message accepted for 
> delivery
> Oct  4 09:57:21 smtp1 MailScanner[7673]: Saved archive copies of 
> j94FuH024035
> Oct  4 10:07:39 smtp1 MailScanner[8930]: Saved archive copies of 
> j94G7W029517 j94FuH024035
> Oct  4 10:18:02 smtp1 MailScanner[1963]: Saved archive copies of 
> j94GHv001891 j94G7W029517 j94FuH024035 j94GHx001902 j94GHv001893 
> j94GHx001907 j94GHx001912 j94GHt001887 j94GHx001908
> Oct  4 10:28:27 smtp1 MailScanner[7135]: Saved archive copies of 
> j94GHv001891 j94G7W029517 j94FuH024035 j94GHx001902 j94GHv001893 
> j94GHx001907 j94GHx001912 j94GHt001887 j94GHx001908
> Oct  4 10:38:44 smtp1 MailScanner[7847]: Saved archive copies of 
> j94GHv001891 j94G7W029517 j94FuH024035 j94GHx001902 j94GHv001893 
> j94GHx001907 j94GHx001912 j94GHt001887 j94GHx001908
> Oct  4 10:49:07 smtp1 MailScanner[16427]: Saved archive copies of 
> j94GHv001891 j94G7W029517 j94FuH024035 j94GHx001902 j94GHv001893 
> j94GHx001907 j94GHx001912 j94GHt001887 j94GHx001908
> Oct  4 10:53:26 smtp1 MailScanner[18665]: Saved archive copies of 
> j94GHv001891 j94GrOJ18662 j94Gr0018612 j94Gqt018568 j94G7W029517 
> j94FuH024035 j94GHx001902 j94Gqv018575 j94GHv001893 j94GHx001907 
> j94Gqv018574 j94Gqt018562 j94Gqq018538 j94Gqr018549 j94GHx001912 
> j94Gqr018543 j94Gqp018536 j94GHt001887 j94GHx001908
> Oct  4 11:03:42 smtp1 MailScanner[18996]: Saved archive copies of 
> j94GHv001891 j94GrOJ18662 j94Gr0018612 j94Gqt018568 j94G7W029517 
> j94FuH024035 j94GHx001902 j94Gqv018575 j94GHv001893 j94GHx001907 
> j94Gqv018574 j94Gqt018562 j94Gqq018538 j94Gqr018549 j94GHx001912 
> j94Gqr018543 j94Gqp018536 j94GHt001887 j94GHx001908
>
> Thanks
>

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