==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 0.9.5-1
- Deployed with iRedMail Easy or the downloadable installer? installer
- Linux/BSD distribution name and version: CentOS Linux release 7.4.1708
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): None
- 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.
====

Greetings,
I've inherited 4 iRedMail servers.
They're set up as outgoing mail  SMTP relays (using RRDNS) for my internal network.
Hostnames structure is as follows: smtp1.mydomain.com, smtp2.mydomain.com, and so on...

Everything works great.
Recently I've implemented DMARC records and noticed that servers send bounce-backs using hostname instead of domain names.
Example bounces from smtp1.mydomain.com comes from MAILER-DAEMON@smtp1.mydomain.com.

Raw SPF checks fail as I dont have SPF records for each hostname, only for mydomain.com. Even if I add SPF records for each hostname, DMARC SPF alignment will fail in strict mode.

So, I'd like to change it so all 4 servers use MAILER-DAEMON@mydomain.com instead.

I've read Postfix docs and it looks like I need to modify myorigin in main.cf
myorigin = mydomain.com
Want to double-check it here that it wont break anything.

Thanks!