==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.6.8
- Deployed with iRedMail Easy or the downloadable installer? downloadable
- Linux/BSD distribution name and version: CentOS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): LDAP
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? Yes
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====
Hello!
Twitter (X) has unresolvable helo hostnames.

NOQUEUE: reject: RCPT from spring-chicken-bg.twitter.com[199.16.156.172]: 450 4.7.1 <spring-chicken-bg.x.com>: Helo command rejected: Host not found; proto=ESMTP helo=<spring-chicken-bg.x.com>

Added into a file helo_access.pcre:

# X.com
/^.*\.x\.com$/ OK

It works, but should we use any other solution for this? It's weird that Twitter(X) does not have resolvable helo hostnames.
Thank you!
Slovenka