SMTP Warnings - Mxtoolbox

TDAndy

Member
Apr 5, 2016
7
0
1
Mangalore, India
cPanel Access Level
Website Owner
Hello Everyone

When i check my domains on mxtoolbox.com

i constantly get these 3 warnings

smtp MYDOMAIN.com Reverse DNS does not match SMTP Banner.
smtp MYDOMAIN.com Warning - Does not support TLS.
smtp MYDOMAIN.com 15.455 seconds - Not good! on Transaction Time.

when i consulted my sysadmin, he informed me that it is cpanel's way of protection and it is automatic and it is fine nothing to worry. i have no choice but to trust the words of my sysadmin.

just a thought if that was the case then mxtoolbox.com would ignore the same and not show the warnings.

i would be glad if someone could help me out here, shed some light and possibly a solution to this problem

Thanks and Regards
Andy
 
Last edited by a moderator:

TDAndy

Member
Apr 5, 2016
7
0
1
Mangalore, India
cPanel Access Level
Website Owner

Thank you very much for your answer, i am a newbie and i have no clue about this, but what i could make out is that it can be fixed but only SMTP banner, but the other 2 warnings TLS and Time is not mentioned anywhere

Would be glad if you let me know a little more ... and that it can be fixed or it is default by cpanel and it cannot be fixed

so that i can let my sysadmin know it can be fixed and get it fixed
 

ChrisI

Technical Analyst II
Mar 24, 2014
67
12
83
cPanel Access Level
Root Administrator
Hello!

The first error:

smtp MYDOMAIN.com Reverse DNS does not match SMTP Banner.

is likely because the server's mailserver isn't responding with the same domain as you are using. You can see what is being returned by connecting to the mailserver with this command, using your domain.

telnet mydomain.com 25

If the domain is on the server's shared IP, it will likely return the server's hostname in the banner. If you need the domain to show up instead, you can put the domain on a dedicated IP address, then use the /etc/mailhelo and /etc/mailips to set the banner for exim for that domain.

On this error:

smtp MYDOMAIN.com Warning - Does not support TLS.

You can test that by issuing the EHLO command when connecting to exim. Exim should give the STARTTLS option by default.

$ telnet cptest1.domain.com 25
Trying 199.191.58.18...
Connected to cptest1.domain.com.
Escape character is '^]'.
220-test3.domain ESMTP Exim 4.88 #1 Tue, 21 Mar 2017 12:45:36 -0400
220-We do not authorize the use of this system to transport unsolicited,
220 and/or bulk e-mail.
EHLO
250-test3.domain.com Hello ng2.cptxoffice.net [208.74.121.106]
250-SIZE 52428800
250-8BITMIME
250-PIPELINING
250-STARTTLS
250 HELP


This error:

smtp MYDOMAIN.com 15.455 seconds - Not good! on Transaction Time.

is normally caused by the 'Introduce a delay into the SMTP transaction for unknown hosts and messages detected as spam.' option under Exim Configuration Manager. This page talks a little more about that.

Exim Configuration Manager - Basic Editor - Documentation - cPanel Documentation

Thanks!
 

TDAndy

Member
Apr 5, 2016
7
0
1
Mangalore, India
cPanel Access Level
Website Owner
Thank you cPanelChrisl for the detailed options

01. SMTP Banner, yes we use a shared server / Ip ... is there anyway to solve this issue without dedicated ip

02. TLS - should we fix this or leave it as it is ?

03. Transaction Time - this option looks good to stop unknown hosts from sending bulk email, so i think we should not fix this

Regards
Andy
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,884
2,250
463
03. Transaction Time - this option looks good to stop unknown hosts from sending bulk email, so i think we should not fix this
Yes, it's a good idea to leave the option enabled.

02. TLS - should we fix this or leave it as it is ?
SMTP TLS is supported. This is discussed on the following post:

Warning: No server certificate defined; TLS connections will fail.

01. SMTP Banner, yes we use a shared server / Ip ... is there anyway to solve this issue without dedicated ip
It should not result in any actual issues with email delivery, other than the warning message you see on MXToolBox. Your server should deliver email successfully provided you follow the guidelines on the following document:

How to Keep your Email out of the Spam Folder - cPanel Knowledge Base - cPanel Documentation

Thank you.