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linuxsendmailline-breakspostfix-mta

Issue with linux postfix /usr/sbin/sendmail: is there a limit on max number of TO addresses?

I have a distribution list with 101 email address that I use for this command

/usr/sbin/sendmail -bm -v -f'[email protected]' -t < /tmp/mailGm8zV8

/tmp/mailGm8zV8:

MIME-Version: 1.0
From: XXXX.SUPPORT <[email protected]>
Subject: test
To: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.006-66
[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.012-66751d212b6
[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.0
[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.031-66751d
[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.037-66751d212b6ca@s
t.com; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; du
[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.050-6
[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.056-66751d212b
[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
m; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.
[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.075-66751
[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.081-66751d212b6f6@
xy.com; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; d
[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.094-
[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.100-66751d212
[email protected]
Content-Type: MULTIPART/mixed; charset="iso-8859-1"; BOUNDARY=4ea15edfb62daf8a1491f8d96d62a7a8

--4ea15edfb62daf8a1491f8d96d62a7a8
Content-Type: TEXT/plain; charset=us-ascii

Example Mail
.

For an unkown reason the distribution list is broken as "empty spaces" are inserted automatically on

Stefano RADAELLI <[email protected]>; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.031 [email protected];

(a the end of this string)

[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.062-6675 [email protected];

(and here)

[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; dummy.093-66751d212 [email protected];

(and here)

[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]

Can anyone help me to understand why it happens and how to avoid it?

Solution

  • Quite likely you hit limit on maximum line length in email or maximum header length.

    Alternative fixes to try:

    • Use multiple To: (or 'Bcc:`) headers e.g. one header per one recipient
    • Pass recipients via command line instead of headers (limit number of recipients e.g. 50)