[Mailman-Users] Mailman + Exim + strange headers

[Natu]

On 05/19/2014 09:56 AM, Sergio Durigan Junior wrote:
> I am not exactly sure, but I wanted to try "fixing" this and see if
> things got better.  The real problem is Google/Gmail tagging the mailing
> list messages as Spam, but since the headers are fine, the cause must be
> something else.

My experience is that goggle sometimes will stop tagging emails as spam
if they have a valid dkim signature. This probably means either:

1) rewriting the from to be your local mailman server and signing the
outbound message with dkim
        OR
2) passing through any valid DKIM signature, which means running a
recent version of mailman and avoid adding any headers/footers which
would break the signature.
        OR
3) possibly having no DKIM signature at all (better than having a
signature which fails verification)

If there is a dkim signature and it fails google will treat it as spam

Goggle and the other various FREEMAILs maintain a rating of the
credibility of email coming from your mailserver.  DKIM signing (with a
signature that will verify correctly) will increase your rating.

I was getting messages like the following from gmail and they stopped
when I implemented DKIM signatures (must be a keysize of at least 1024):

Jan 21 16:36:06 myserv postfix/smtp[5374]: 68972108248: host
gmail-smtp-in.l.google.com[74.125.142.26] said: 421-4.7.0 [1.2.3.4] Our
system has detected an unusual rate of 421-4.7.0 unsolicited mail
originating from your IP address. To protect our 421-4.7.0 users from
spam, mail sent from your IP address has been temporarily 421-4.7.0
blocked. Please visit http://www.google.com/mail/help/bulk_mail.html 421
4.7.0 to review our Bulk Email Senders Guidelines. ih5si10430009icb.36 -
gsmtp (in reply to end of DATA command)

You may also benefit from using DMARC (probably not technically, but
politically).

You may not be doing bulk mailings, but the information here may be helpful:
https://support.google.com/mail/answer/81126

Also you can try things like
https://duckduckgo.com/?q=gmail+flags+my+mail+as+spam&t=canonical
<https://duckduckgo.com/?q=gmail+flags+my+mail+as+spam&t=canonical>
Also check http://multirbl.valli.org/ to make sure your mail server is
not on any DNS blocklists.

Nataraj