Reverse DNS is not a valid Hostname

helix01

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Jun 19, 2014
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I ran a mxtoolbox report on our domain all the checks are coming green except one on top i just can't figure out how to fix this any help on this would be great just to keep the security please note i have change our site name to abcxyz.com with 1.1.1.1 its ip address:

SMTP Valid Hostname Reverse DNS is not a valid Hostname More Info

SMTP Reverse DNS Mismatch OK - 1xx.xxx.xxx.xx resolves to abcxyz.com
SMTP Banner Check OK - Reverse DNS matches SMTP Banner
SMTP TLS OK - Supports TLS.
SMTP Connection Time 0.859 seconds - Good on Connection time
SMTP Open Relay OK - Not an open relay.
SMTP Transaction Time 3.344 seconds - Good on Transaction Time



WHM is is the dns server and rdns entry in our server provider is also set just dont know what i am missing:

our dns listings for this domain from our whm:

Code:
abcxyz.com.    3600    IN    A    1.1.1.1    Edit   Delete
localhost.abcxyz.com.    14400    IN    A    127.0.0.1    Edit   Delete
mail.abcxyz.com.    3600    IN    A    1.1.1.1    Edit   Delete
www.abcxyz.com.    3600    IN    CNAME    abcxyz.com    Edit   Delete
ftp.abcxyz.com.    3600    IN    A    1.1.1.1    Edit   Delete
cpanel.abcxyz.com.    14400    IN    A    1.1.1.1    Edit   Delete
webdisk.abcxyz.com.    14400    IN    A    1.1.1.1    Edit   Delete
webmail.abcxyz.com.    14400    IN    A    1.1.1.1    Edit   Delete
pop.abcxyz.com.    3600    IN    CNAME    mail    Edit   Delete
abcxyz.com.    3600    IN    TXT    v=spf1 +a +mx +ip4:1.1.1.1 ~all    Edit   Delete
whm.abcxyz.com.    14400    IN    A    1.1.1.1    Edit   Delete
cpcalendars.abcxyz.com.    14400    IN    A    1.1.1.1    Edit   Delete
cpcontacts.abcxyz.com.    14400    IN    A    1.1.1.1    Edit   Delete
ns01.whmserver.com.abcxyz.com.    3600    IN    A    2.2.2.2    Edit   Delete
ns02.whmserver.com.abcxyz.com.    3600    IN    A    3.3.3.3    Edit   Delete
 
Last edited by a moderator:

24x7server

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Hello,

What is current hotname of your server? Please contact your server provider with your hotname and main server IP and ask them to setup the RDNS for your server.
 

helix01

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thanks for the reply, the current hostname for server is test1.domain.com an rdns is setup on the OVH portal for this host to 4.4.4.4
 

helix01

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Do i need to create a hostname A entry under the DNS zone for abcxyz.com for the current host, I still went ahead and create an entry of A record for test1.domain.com in abcxyz.com

now it looks like this but no luck : (

test1.domain.com.abcxyz.com. 3600 IN A 4.4.4.4 Edit Delete
 

lx24

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Oct 2, 2014
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Hi,

You can create new DNS zone for your server host name.

A record of test1.domain.com should point and resolve to 4.4.4.4

And rdns of 4.4.4.4 should be to test1.domain.com

still issue? hit "post reply"
 

helix01

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Jun 19, 2014
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Hi,

You can create new DNS zone for your server host name.

A record of test1.domain.com should point and resolve to 4.4.4.4

And rdns of 4.4.4.4 should be to test1.domain.com

still issue? hit "post reply"
Just checked my WHM there is already a zone for our server hostname which contains A records and other records this, plus i am able to do nslookup via servername or ip and resolve 100% correctly to server OVH RDNS records are also identical and refer to the IP and name of the server host.

I am literally pulling my hair at this stage......have read dozens forum not much out there for this specific issue..

I found this post but didn't get anywhere with this : https://forums.cpanel.net/threads/r...e-smtp-greeting-must-have-an-a-record.473961/
 

cPanelMichael

Administrator
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Apr 11, 2011
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Just checked my WHM there is already a zone for our server hostname which contains A records and other records this, plus i am able to do nslookup via servername or ip and resolve 100% correctly to server OVH RDNS records are also identical and refer to the IP and name of the server host.
Hello :)

It's very possible that you have configured it correctly and the third-party utility you are using to test this with is checked cached records. You may want to test with a different website, or rely on command line tools such as "nslookup" or "dig".

Thank you.
 

helix01

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Jun 19, 2014
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Hello :)

It's very possible that you have configured it correctly and the third-party utility you are using to test this with is checked cached records. You may want to test with a different website, or rely on command line tools such as "nslookup" or "dig".

Thank you.
Thanks Michael for pointing out I went out and tested with another provide check for MX and SMTP records and came out not a single issue so seems like only specific to mxtoolbox for some reason this issue.

thanks for the help on this, lesson learn always test with two different providers at the least.
 

cPanelMichael

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Apr 11, 2011
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I am happy to see the results are normal at another provider's utility. Thank you for updating us with the outcome.