HELO problem /Reverse DNS is not a Valid Hostname

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obastard
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HELO problem /Reverse DNS is not a Valid Hostname

Post by obastard » 2021-06-17 14:42

Hi
I keep getting the notorious "Reverse DNS is not a Valid Hostname", but localhost under smtp is set up to have the correct domain. And if I do a reverse DNS it resolves to the domain....
Any ideas of what's wrong?


Connecting to 95.217.145.13

220 rednet2.dk ESMTP [164 ms]
EHLO keeper-us-east-1c.mxtoolbox.com
250-rednet2.dk
250-SIZE 50000000
250-AUTH LOGIN
250 HELP [211 ms]
MAIL FROM:<supertool@mxtoolboxsmtpdiag.com>
250 OK [673 ms]
RCPT TO:<test@mxtoolboxsmtpdiag.com>
530 SMTP authentication is required. [215 ms]

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jimimaseye
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Re: HELO problem /Reverse DNS is not a Valid Hostname

Post by jimimaseye » 2021-06-17 15:10

obastard wrote:
2021-06-17 14:42
I keep getting the notorious "Reverse DNS is not a Valid Hostname",
Where?
5.7 on test.
SpamassassinForWindows 3.4.0 spamd service
AV: Clamwin + Clamd service + sanesecurity defs : https://www.hmailserver.com/forum/viewtopic.php?f=21&t=26829

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SorenR
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Re: HELO problem /Reverse DNS is not a Valid Hostname

Post by SorenR » 2021-06-17 15:58

obastard wrote:
2021-06-17 14:42
Hi
I keep getting the notorious "Reverse DNS is not a Valid Hostname", but localhost under smtp is set up to have the correct domain. And if I do a reverse DNS it resolves to the domain....
Any ideas of what's wrong?


Connecting to 95.217.145.13

220 rednet2.dk ESMTP [164 ms]
EHLO keeper-us-east-1c.mxtoolbox.com
250-rednet2.dk
250-SIZE 50000000
250-AUTH LOGIN
250 HELP [211 ms]
MAIL FROM:<supertool@mxtoolboxsmtpdiag.com>
250 OK [673 ms]
RCPT TO:<test@mxtoolboxsmtpdiag.com>
530 SMTP authentication is required. [215 ms]
rednet2.dk is your domain. All units on the Internet have a FQDN ... an A-record and a PTR record.

mail.rednet2.dk A 95.217.145.13
rednet2.dk MX 10 mail.rednet2.dk
rednet2.dk MX 20 <optional backupmx from ISP>

95.217.145.13 PTR mail.rednet2.dk

Your hostname in hMailServer must be "mail.rednet2.dk"
SørenR.

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Word used by programmers when they do not want to explain what they did.

obastard
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Re: HELO problem /Reverse DNS is not a Valid Hostname

Post by obastard » 2021-06-17 21:52

Hi Steven
Thanks - but I tried that already -it gives same not valid error:

Connecting to 95.217.145.13

220 mail.rednet2.dk ESMTP [169 ms]
EHLO keeper-us-east-1c.mxtoolbox.com
250-mail.rednet2.dk
250-SIZE 50000000
250-AUTH LOGIN
250 HELP [216 ms]
MAIL FROM:<supertool@mxtoolboxsmtpdiag.com>
250 OK [342 ms]
RCPT TO:<test@mxtoolboxsmtpdiag.com>
530 SMTP authentication is required. [216 ms]

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SorenR
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Re: HELO problem /Reverse DNS is not a Valid Hostname

Post by SorenR » 2021-06-17 22:06

95.217.145.13 resolve to rednet2.dk and not mail.rednet2.dk
SørenR.

Algorithm (noun.)
Word used by programmers when they do not want to explain what they did.

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jimimaseye
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Re: HELO problem /Reverse DNS is not a Valid Hostname

Post by jimimaseye » 2021-06-17 22:19

Again, i ask.....
jimimaseye wrote:
2021-06-17 15:10
obastard wrote:
2021-06-17 14:42
I keep getting the notorious "Reverse DNS is not a Valid Hostname",
Where?
You haven't shown any evidence of this claim yet.
5.7 on test.
SpamassassinForWindows 3.4.0 spamd service
AV: Clamwin + Clamd service + sanesecurity defs : https://www.hmailserver.com/forum/viewtopic.php?f=21&t=26829

obastard
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Re: HELO problem /Reverse DNS is not a Valid Hostname

Post by obastard » 2021-06-17 22:42

This was when changing to mail.rednet2.dk - and rednet2.dk gives same result.
Udklip.PNG

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jimimaseye
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Re: HELO problem /Reverse DNS is not a Valid Hostname

Post by jimimaseye » 2021-06-17 22:51

Care to post the screen shot including the results?
5.7 on test.
SpamassassinForWindows 3.4.0 spamd service
AV: Clamwin + Clamd service + sanesecurity defs : https://www.hmailserver.com/forum/viewtopic.php?f=21&t=26829

obastard
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Re: HELO problem /Reverse DNS is not a Valid Hostname

Post by obastard » 2021-06-17 23:02

Udklip.PNG

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jimimaseye
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Re: HELO problem /Reverse DNS is not a Valid Hostname

Post by jimimaseye » 2021-06-17 23:26

This is nothing to do with hmailserver host name, it's your dns records.

Your PTR record is rednet2.dk which is a Domain name. The RFC guidelines say that is must be a hostname such as mail.rednet2.dk. Most systems won't care that it is a domain, but since it's against the RFC guidelines, it shows a warning.
5.7 on test.
SpamassassinForWindows 3.4.0 spamd service
AV: Clamwin + Clamd service + sanesecurity defs : https://www.hmailserver.com/forum/viewtopic.php?f=21&t=26829

obastard
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Re: HELO problem /Reverse DNS is not a Valid Hostname

Post by obastard » 2021-06-17 23:34

ok thanks :)

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