[SOLVED] Verify receivers multiple entry DNS zone

[ValentinDe]

Hello

Today i have a strange behavior with domain <-> ip verification.

The message refusing the mail:

Dec 11 16:28:15 mail-gw01 postfix/smtpd[28144]: warning: hostname relais-inet.xx.com does not resolve to address 80.xx.66.xx: No address associated with hostname
Dec 11 16:28:15 mail-gw01 postfix/smtpd[28144]: connect from unknown[80.xx.66.xx]
Dec 11 16:28:15 mail-gw01 postfix/smtpd[28144]: NOQUEUE: reject: RCPT from unknown[80.xx.66.xx]: 450 4.7.25 Client host rejected: cannot find your hostname, [80.xx.66.xx]; from=<xx.xx@xx.com> to=<xx.xx@xx.fr> proto=ESMTP helo=<relais-inet.xx.com>
Dec 11 16:28:15 mail-gw01 postfix/smtpd[28144]: disconnect from unknown[80.xx.66.xx] ehlo=2 starttls=1 mail=1 rcpt=0/1 data=0/1 rset=1 quit=1 commands=6/8

(ip anonymized)

This ip send email to my server:
80.xx.66.xx, when i resolve the reverse is : relais-inet.xx.com, this is good.
But when i dig the reverse ip of relais-inet.xx.com is have lot of ips:

Non-authoritative answer:
Name: relais-inet.xx.com
Address: 80.xx.210.xx
Name: relais-inet.xx.com
Address: 80.xx.210.xx
Name: relais-inet.xx.com
Address: 80.xx.66.xx
Name: relais-inet.xx.com
Address: 80.xx.210.xx
Name: relais-inet.xx.com
Address: 80.xx.66.xx

Do you any idea about this bug ?

Thanks

Version: pmg-api/6.3-5/40d25ec2 (running kernel: 5.4.65-1-pve)

 

[hata_ph]

confirm only your pmg not resolve the hostname properly?

 

[ValentinDe]

confirm only your pmg not resolve the hostname properly?

Yes, the server resolve properly, log in post come from srv where pmg is installed.

 

[hata_ph]

confirm your pmg can only not resolve properly for 1 domain or all domain?

 

[ValentinDe]

It’s the first case. I don’t know if is all domain multiple A input or only this

 

[hata_ph]

what is the DNS on your PMG for hostname resolve?
have you try using other DNS settings?
is there any firewall rules blocking/effecting PMG accessing internet?

 

[ValentinDe]

No network problem. All other services work. I think is only the verification when domain return multiple IP

 

[Stoiko Ivanov]

what does

dig relais-inet.xx.com
dig -x 80.xx.66.xx

output, when run on the PMG?
(you might need to install dnsutils)

 

[ValentinDe]

Ok, i find the problem. At the date of the logs the DNS server stop response to certain query.

 

[Stoiko Ivanov]

Glad you found the root-cause!
Please mark the thread as 'SOLVED' - this helps other users in a similar situation

Thanks!