1 Topic by MuPp3t33r

  • MuPp3t33r
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Topic: Recipient address rejected: User unknown in virtual mailbox table

==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 0.9.9 MARIADB edition.
- Deployed with iRedMail Easy or the downloadable installer? Downloadable
- Linux/BSD distribution name and version: Debian 9
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):  MySQL
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====


I have a domain (example.com) that has multiple different email servers across the country for our different branch offices, with Mimecast handling the mail routing rules.

Just set up a iRedMail server for one of the sites and so far it works perfectly with the exception of users emailing out to the other branches:
"Recipient address rejected: User unknown in virtual mailbox table"
Which makes perfect sense, because the user doesn't exist on THAT server obviously, but my main question is: how do I get Postfix to use my Mimecast relayhost IF the recipient (at example.com) is not in the mailbox tables?

----

Spider Email Archiver: On-Premises, lightweight email archiving software developed by iRedMail team. Supports Amazon S3 compatible storage and custom branding.

2 Reply by ZhangHuangbin

  • ZhangHuangbin
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Re: Recipient address rejected: User unknown in virtual mailbox table

I don't know how mimecast works... maybe you can get some help from mimecast? Sorry.

3 Reply by MuPp3t33r (edited by MuPp3t33r 2020-10-30 19:25:50)

  • MuPp3t33r
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Re: Recipient address rejected: User unknown in virtual mailbox table

ZhangHuangbin wrote:

I don't know how mimecast works... maybe you can get some help from mimecast? Sorry.

I did manage to figure it out, although I think maybe you somewhat misunderstood my original post, i probably could have explained better, so not your fault smile

Essentially how I have it set up is that there are multiple email servers across the country that both send AND receive with the same domain, but each branch has their own set of email addresses not the same across branches. Hence when trying to email other branches then Postfix was was seeing the same domain name and trying to lookup locally instead of directing it to the relayhost.
The mention of Mimecast only relates to how mails are delivered to the correct server (for incoming mails)

My solution was to create a transport rule in Postfix

MuPp3t33r wrote:

internaluser@domain.tld    dovecot

domain.tld       smtp:za-smtp-outbound-1.mimecast.co.za
*                  :

This way, internal mails will go to the local mailbox via dovecot, and everything else for that domain goes to the relayhost.

Would there be a better way to achieve this?