Where/when to insert a missing Message-ID

2 msg	Postfix SASL Help
6 msg	Slowing down postfix
2 msg	need help deciphering a line
4 msg	Postfix SMTP server: errors from something.net[...
4 msg	2.5.0-RC and 2.6 should recognize FreeBSD 8
9 msg	Postfix not following my access file.
3 msg	postfix logs delay, delays, dsn
3 msg	Best way to shutdown postfix prior to servicing...
1 msg	the bounce process hangs a mail (?)
3 msg	messages destined for content_filter stuck in d...
2 msg	Domain in username
5 msg	missing authentication on recipient
5 msg	postfixadmin
5 msg	check_policy_service before reject_rbl_client
9 msg	MXBackup via LDAP
5 msg	header and body check exemptions
5 msg	Relay recipient maps and relocated users
4 msg	mail forwarding loop :: SPAM
3 msg	transport_maps how to match mx's

Where/when to insert a missing Message-ID
\ Mark Martinec (21 Jan 2008)
. \ (Wietse Venema) (21 Jan 2008)

Subject:	Where/when to insert a missing Message-ID
Group:	Postfix-users
From:	Mark Martinec
Date:	21 Jan 2008

Here is one not-too-important issue.

When checking some incoming mail signed with historical DomainKeys signatures
without an 'h' tag (no list of signed headers, implying all are signed),
I see one source of these messages (bulk, but legitimate commercial junk)
which is consistently failing signature validation because the sender did not
provide a Message-ID in its posting, and our receiving Postfix appended a
Message-ID at the end of the header, this breaking a signature.

I can see three possibilities:
- change Postfix to prepend a missing Message-ID, instead of appending it;
- change Postfix to add a missing Message-ID only for mail matching
the local_header_rewrite_clients setting;
- not to bother (as DKIM no longer suffers this problem, making an 'h'
tag obligatory)

Mark