I'm referring to post https://i-mscp.net/index.php/Thread/13074-SRS-Plugin/
But this case seems a bit different. In addition to the SRS subject I'm currently watching a special issue in the case of mail forwarding.
Setup is as following:
- 2 virtual servers, each with its own IP and some domains as clients.
- Identical configurations on every machine.
- OS: Debian Jessie, updated
- i-MSCP: latest stable 1.4.7, any configuration left to defaults
- MTA_SERVER => 'postfix',
- PO_SERVER => 'dovecot',
- SPF Plugin 1.2.0
Few imap accounts, some mail forwarders as well as catchall are set on some domains.
Following is the process that happens.
2. Recepient server SSS.info has set a forward on wpadmin02
Tries to proceed forwarding
"wpadmin02@SSS.info" -> catchall@DDD.net
i. e. from VM2 back to VM1
Where only by chance DDD.net is located again on VM1
Part of mail message is:
- This is the mail system at host VM2.DDD.net.I'm sorry to have to inform you that your message could notbe delivered to one or more recipients. It's attached below.For further assistance, please send mail to postmaster.If you do so, please include this problem report. You candelete your own text from the attached returned message. The mail system<catchall@DDD.net> (expanded from <wpadmin02@SSS.info>): host VM1.DDD.net[IP VM1] said: 550 5.7.1 <catchall@DDD.net>: Recipient address rejected: Please see http://www.openspf.net/Why?s=mfrom;id=webmaster%40BBB.org;ip=IP VM2;r=VM1.DDD.net (in reply to RCPT TO command)
3. Whole Message is submitted to webmaster@BBB.org as bounced mail
This is, what I received.
Now the curious fact, wether related to SRS or not and in difference to bounced mails by providers like gmx.net or web.de:
SPF txt entries in any mentioned domain is as follows
"v=spf1 ip4:[IP adress or net range of VM1] ip4:[IP adress or net range of VM2] +a +mx ~all"
That means, any domain is allowed to send from each VM.
The correct configuration is confirmed by SPF website.
- DDD.net rejected a message that claimed an envelope sender address of webmaster@BBB.org.
- VM1.DDD.net received a message from VM2.DDD.net (IP...) that claimed an envelope sender address of webmaster@BBB.org.
- The domain BBB.org has authorized VM2.DDD.net (IP...) to send mail on its behalf, so the message should have been accepted. It is impossible for us to say why it was rejected.
Current possible solutions:
- I could create imap accounts for some purposes. Here: for WP Admin contact.
- Trying to avoid forwarding generally, as concerning the SRS problems, this is a growing reason for bounced mails as SPF gets more implemented
- One may think, that the reason is not related to forwarding in general but in forwarding as result of a catchall. I'm forwarding several catchalls to one general catchall address, which works fine so far. May be I have to recreate catchall adresses for each domain seperately again.
This post is intended foremost as a report and I myself will keep an eye on that. Looking for other solutions. As far as today I dindn't found some.