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Date: Fri, 22 Dec 2023 17:41:56 +0100
From: Solar Designer <>
Subject: Fwd: [pfx-ann] Postfix stable release 3.8.4

----- Forwarded message from Wietse Venema via Postfix-announce <> -----

To: Postfix announce <>
Date: Fri, 22 Dec 2023 11:30:21 -0500 (EST)
CC: Postfix users <>
Subject: [pfx-ann] Postfix stable release 3.8.4
From: Wietse Venema via Postfix-announce <>
Reply-To: Wietse Venema <>

[An on-line version of this announcement will be available at]

Fixed with Postfix 3.8.4:

  * Security: this release adds support to defend
    against an email spoofing attack (SMTP smuggling) on
    recipients at a Postfix server. For background, see

    Sites concerned about SMTP smuggling attacks should enable this
    feature on Internet-facing Postfix servers. For compatibility
    with non-standard clients, Postfix by default excludes clients
    in mynetworks from this countermeasure.

    The recommended settings are:

	# Optionally disconnect remote SMTP clients that send bare newlines,
	# but allow local clients with non-standard SMTP implementations
	# such as netcat, fax machines, or load balancer health checks.
	smtpd_forbid_bare_newline = yes
	smtpd_forbid_bare_newline_exclusions = $mynetworks

    The smtpd_forbid_bare_newline feature is disabled by default.

You can find the updated Postfix source code at the mirrors listed at

Postfix-announce mailing list --
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----- End forwarded message -----

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