1 Topic by gaudec

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Topic: Hostname verification errors (FCRDNS)

==== Required information ====
- iRedMail version 0.9.5-1
- Ubuntu Trusty 14.04.4, MySQL, Apache
- no iRedAdmin-Pro
====

Hi, I'm wondering why Logwatch shows me this:

       63   Hostname verification errors (FCRDNS) ---------------------------------------------------
       63      Does not resolve to address
       61         127.0.0.1        mail.MYDOMAIN.com

(where MYDOMAIN is my domain).

Everything seems to be working fine. I can send and receive e-mails (as far as I know). The number 61 matches the "Ham" (clean passed).

If I test my IP at http://ipadmin.junkemailfilter.com/rdns.php (and others) it shows success, "The IP address for the reverse lookup name matches the original IP".

Is it something I should ignore? Why does it show 127.0.0.1?

----

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2 Reply by ZhangHuangbin

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Re: Hostname verification errors (FCRDNS)

Is "mail.mydomain.com" your server hostname? If yes, please add it in /etc/hosts and /var/spool/postfix/etc/hosts.

3 Reply by gaudec

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Re: Hostname verification errors (FCRDNS)

My files look like this:

##.##.##.##     mail.MYDOMAIN.com mail
127.0.0.1       mail.MYDOMAIN.com mail
127.0.0.1       localhost localhost.localdomain localhost4 localhost4.localdomain4
::1             localhost localhost.localdomain localhost6 localhost6.localdomain6

At some point I added the first line to fix an issue I don't remember. I think it was about e-mail being received as coming from 127.0.0.1.

If I remove the first line, should I fix my e-mail sending somehow?

4 Reply by ZhangHuangbin

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Re: Hostname verification errors (FCRDNS)

Why not merge those 2 "127.0.0.1" lines?

5 Reply by gaudec

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Re: Hostname verification errors (FCRDNS)

ZhangHuangbin wrote:

Why not merge those 2 "127.0.0.1" lines?

I did. Now both /etc/hosts and /var/spool/postfix/etc/hosts look identical, with one 127.0.0.1 on each, but it still complains.

I see this kind of messages on syslog:

Jan  9 16:42:59 mail postfix/smtpd[1027]: warning: hostname mail.xxx.com does not resolve to address 127.0.0.1
Jan  9 16:42:59 mail postfix/smtpd[1027]: connect from unknown[127.0.0.1]

Any other ideas? smile

6 Reply by ZhangHuangbin

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Re: Hostname verification errors (FCRDNS)

You replied in 4 months ...

*) What's your server hostname? Show us command output: "hostname -f".
*) Show us full /etc/hosts and /var/spool/postfix/etc/hosts  please.

7 Reply by gaudec

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Re: Hostname verification errors (FCRDNS)

$ hostname -f
mail.myserver.com

$ cat /etc/hosts
80.86.XX.XX     mail.myserver.com mail
127.0.0.1       mail.myserver.com mail localhost localhost.localdomain localhost4 localhost4.lo

::1             localhost localhost.localdomain localhost6 localhost6.localdomain6

$ cat /var/spool/postfix/etc/hosts 
80.86.XX.XX     mail.myserver.com mail
127.0.0.1       mail.myserver.com mail localhost localhost.localdomain localhost4 localhost4.lo

::1             localhost localhost.localdomain localhost6 localhost6.localdomain6

Thank you. The issue did not seem to be critical, that's why it took me time to reply.

8 Reply by ZhangHuangbin

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Re: Hostname verification errors (FCRDNS)

both 'hosts' files look fine.

Not sure whether this Postfix setting in main.cf can fix your issue:

smtp_host_lookup = dns, native

9 Reply by gaudec

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Re: Hostname verification errors (FCRDNS)

I tried, and restarted postfix, but unfortunately I still get the same "Does not resolve to address" FCRDNS errors. If the server seems to work, what is the consequence of these errors?

10 Reply by ZhangHuangbin

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Re: Hostname verification errors (FCRDNS)

Try this, add "multi on" in /etc/host.conf.

11 Reply by gaudec

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Re: Hostname verification errors (FCRDNS)

I see "multi on" already there:

 order hosts,bind
 multi on

12 Reply by ZhangHuangbin

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Re: Hostname verification errors (FCRDNS)

No idea right now. Sorry.
I suggest post to postfix mailing list to get some help from more postfix users.

13 Reply by gaudec

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Re: Hostname verification errors (FCRDNS)

Thank for the tip. I fixed it by removing mail.myserver.com from 127.0.0.1. So now mail.myserver.com only points to the server IP. No more FCRDNS errors.