[Mimedefang] Milter: data, reject=451 4.7.1 Please try again later

[Paul Murphy]

Yes:

> May  9 20:38:51 wuhan sendmail[20860]: [ID 801593 mail.info]
h4A2AAsR020860:
> from=<lstevens at k2architects.com>, size=449133930, class=0, nrcpts=1,

Someone tried to send you half a gigabyte in your mail, and your system
attempted to process it.  Since the Mimedefang spool directory is on your
swap space, and in addition Mimedefang has to allocate enough memory to
process the message, you ran out of memory and swap.  Not surprising really -
there are few systems which could cope with a message this size.

> May  9 20:40:20 wuhan mimedefang[13560]: [ID 480956 mail.warning]
>h4A2AAsR020860: writen failed: No space left on device line 979

Your "df -k" display is of course after the event - during processing, one of
the file systems filled up, almost certainly your spool directory.  

The solution is to configure Sendmail to limit the size of messages, using 

define(`SMTP_MAILER_MAX',15000000)

in your .mc file - i.e. approx 15Mb in this case.

Alternatively, if you really must transfer files of this size around, use FTP
or an HTTP upload, and ZIP the file - MIME encoding adds 50% to the size, so
the 450Mb mail message probably has a 300Mb attachment set, which could
compress down to 150Mb or less.

Best Wishes,

Paul.