1 Topic by KNERD

  • KNERD
  • Member
  • Offline
  • Registered: 2019-01-25
  • Posts: 63

Topic: Server rejecting "dynamic" IP host when it is not

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

Here is the issue.

Jan  3 19:18:09 mail postfix/smtpd[25359]: NOQUEUE: reject: RCPT from 212.183-56-198.rdns.joshwhotv.com[198.56.183.212]: 554 5.7.1 <212.183-56-198.rdns.joshwhotv.com>: Helo command rejected: ACCESS DENIED. Your email was rejected because the sending mail server appears to be on a dynamic IP address that should not be doing direct mail delivery (212.183-56-198); from=<xxxxx@joshwhotv.com>

According to mxtoolbox.com all is fine on their end, so why is the email; server giving a false positive?

----

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
  • ZhangHuangbin
  • iRedMail Developers
  • Offline
  • Registered: 2009-05-06
  • Posts: 30,770

Re: Server rejecting "dynamic" IP host when it is not

KNERD wrote:

212.183-56-198.rdns.joshwhotv.com

It's rejected due to this HELO hostname contains IP address digits (212.183-56-198).

Usually mail server hostname does not contain IP address, this makes them looks like spammer.
Are you saying this sender server is a normal mail server? Or you are curious why it's rejected?

3 Reply by KNERD

  • KNERD
  • Member
  • Offline
  • Registered: 2019-01-25
  • Posts: 63

Re: Server rejecting "dynamic" IP host when it is not

I thought i had replied to this earlier. I guess I did not press the Submit button.

It is a normal server hosted in Cloudflare as far as I can tell.

4 Reply by ZhangHuangbin

  • ZhangHuangbin
  • ZhangHuangbin
  • iRedMail Developers
  • Offline
  • Registered: 2009-05-06
  • Posts: 30,770

Re: Server rejecting "dynamic" IP host when it is not

It's about the HELO hostname, not the IP address actually.

- You can whitelist HELO hostname on your side in /etc/postfix/helo_access.pcre.
- Contact this server admin and ask him/her to set a proper server hostname or HELO hostname.