Duplicate CC mails form yahoo.com

[Dnmax]

Server config is DirectAdmin 1.37.0 Exim 4.73+Spamblocker4 exim.conf dovecot 2.0.9

Alias config as follows

user1 -> commonmailbox, [email protected]
user2 -> commonmailbox, [email protected]
user3 -> commonmailbox, [email protected]

We use the commonmailbox to archive mails coming to all users.

Issue : When someone sends mail from yahoo.com as well as few other servers like

To: [email protected]
CC: [email protected], [email protected]

We are getting 3 copies of the same mail in the commonmailbox instead of one copy.

Any solution for this issue?

 

[nobaloney]

Your exim/mainlog should tell you what's going on.

But at first guess, each user is also forwarding to commonmailbox.

Jeff

 

[Dnmax]

Your exim/mainlog should tell you what's going on.

But at first guess, each user is also forwarding to commonmailbox.

Jeff

I checked the To: and CC: fields they are all correct.

This problem is happening only with sending hosts connecting with TLS, RSA-SHA etc connection, with multiple CC: email ID's

The exim.conf setting for TLS is

#EDIT#23:
tls_certificate = /etc/exim.cert
tls_privatekey = /etc/exim.key
tls_require_ciphers = ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:-LOW:-SSLv2:-EXP
tls_advertise_hosts = *
#auth_over_tls_hosts = *

 

[Dnmax]

I found solution to eliminate duplicate CC mails once they are downloaded to the local mail server where the mails are archived.

Adding the following in the .procmailrc in the commonmailbox folder

:0 Wh: msgid.lock
| formail -D 8192 msgid.cache

will keep a cache of message ID's and eliminate duplicate messages and store only one copy per unique message ID.

This does not resolve the issue fully since duplicate messages has to be downloaded, unnecessary waste of bandwidth when these messages has large attachments.

The duplicate CC mails are coming from few other servers apart from yahoo.com. Any idea why this is happening?