Exim banner, mail headers and resellers with own ip

WebCraft

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May 29, 2008
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standard exim.conf:
smtp_banner = "${primary_hostname} ESMTP Exim ${version_number} \
blah-blah-blah

I have changed to:

smtp_active_hostname = ${if exists {/etc/mail_reverse_dns}{${lookup{$interface_address}lsearch{/etc/mail_reverse_dns} \
{$value}{$primary_hostname}}}{$primary_hostname}}

smtp_banner = "${smtp_active_hostname} ESMTP Exim ${version_number} \
blah-blah-blah

Now I can see a reseller's hostname in banner (telnet ip 25). But in headers I still see 'received by server_primary_hostname'. How can I force exim to change hostname in headers?

Best regards, Arthur
 

markhard

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Apr 22, 2004
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i'm looking answer too regarding this problem.

i setup a domain on my server to use a dedicated IP for sending outgoing emails. it seems to work fine at some point. if i send email to gmail.com i can see that the sender IP is the dedicated IP assigned for the domain, but.. when i check on MX Lookup Tool - Check your DNS MX Records online - MxToolbox SMTP diagnostic, it's said "Warning - Reverse DNS does not match SMTP Banner"

it seems that although the HELO and IP is set to dedicated IP setting, the smtp_banner is still using server's hostname which cause the warning: "Warning - Reverse DNS does not match SMTP Banner"

any solution on this?

i found a tutorial to fix this but it requires manual configuration on exim.conf which of course will be erased on cpanel update (hence must redo every time we do cpanel update): Exim customization
 

cPanelDon

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it seems that although the HELO and IP is set to dedicated IP setting, the smtp_banner is still using server's hostname which cause the warning: "Warning - Reverse DNS does not match SMTP Banner"

any solution on this?
What is your cPanel version number? If needed, this can be found in the upper-right corner of WebHost Manager (WHM) or obtained via root CLI/SSH access as seen below:
Code:
# /usr/local/cpanel/cpanel -V
Please provide the output from the following command:
Code:
# grep per_domain_mailips /etc/exim.conf.localopts && stat /var/cpanel/per_domain_mailips
 

markhard

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Apr 22, 2004
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What is your cPanel version number? If needed, this can be found in the upper-right corner of WebHost Manager (WHM) or obtained via root CLI/SSH access as seen below:
Code:
# /usr/local/cpanel/cpanel -V
CPanel version: WHM 11.28.52

Please provide the output from the following command:
Code:
# grep per_domain_mailips /etc/exim.conf.localopts && stat /var/cpanel/per_domain_mailips
per_domain_mailips=0
stat: cannot stat `/var/cpanel/per_domain_mailips': No such file or directory
 

cPanelDon

cPanel Quality Assurance Analyst
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Nov 5, 2008
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CPanel version: WHM 11.28.52

per_domain_mailips=0
stat: cannot stat `/var/cpanel/per_domain_mailips': No such file or directory
The information provided leads me to believe that the option that will automatically manage the files /etc/mailhelo and /etc/mailips is not enabled via the Exim Configuration Editor in WHM. Are one or both of the other (non-automatic) options enabled to allow the two files to be managed manually?

Providing output from the following command will help to confirm which options may be enabled:
Code:
# egrep -Hn "(custom_mailhelo|custom_mailips|per_domain_mailips)" /etc/exim.conf.localopts && stat /var/cpanel/custom_mailhelo /var/cpanel/custom_mailips /var/cpanel/per_domain_mailips
Related menu path and documentation:
 

markhard

Well-Known Member
Apr 22, 2004
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The information provided leads me to believe that the option that will automatically manage the files /etc/mailhelo and /etc/mailips is not enabled via the Exim Configuration Editor in WHM. Are one or both of the other (non-automatic) options enabled to allow the two files to be managed manually?
it's indeed not enabled, I choose to manually manage the files /etc/mailhelo and /etc/mailips. however this is not my question.

my question was about the smtp_banner which is still using the hostname of the server and not using the assigned IP rDNS, hence i got "Warning - Reverse DNS does not match SMTP Banner" error when checking the domain's mail IP on MX Lookup Tool - Check your DNS MX Records online - MxToolbox
 

cPanelDon

cPanel Quality Assurance Analyst
Staff member
Nov 5, 2008
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Houston, Texas, U.S.A.
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it's indeed not enabled, I choose to manually manage the files /etc/mailhelo and /etc/mailips. however this is not my question.

my question was about the smtp_banner which is still using the hostname of the server and not using the assigned IP rDNS, hence i got "Warning - Reverse DNS does not match SMTP Banner" error when checking the domain's mail IP on MX Lookup Tool - Check your DNS MX Records online - MxToolbox
I apologize. I misunderstood the circumstances, and I confirm what you have described. I would believe it is normal for the hostname to be used in the smtp_banner. To help me better understand the difficulty, please elaborate in detail about the specific problem that you are encountering.
 

cPanelDon

cPanel Quality Assurance Analyst
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Nov 5, 2008
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I tried reproducing the message reported at the mxtoolbox web site, but I was unable to trigger the same message. The following is munged output using the "SMTP" test at th mxtoolbox web site:
Code:
220-server1.domain.tld ESMTP Exim 4.69 #1 Fri, 24 Dec 2010 21:58:57 -0600 We do not authorize the use of this system to transport unsolicited, and/or bulk e-mail.

Not an open relay.
 0 seconds - Good on Connection time
 2.527 seconds - Good on Transaction time
 OK - 1.2.3.4 resolves to n4.3-2-1.domain.tld
 OK - Reverse DNS matches SMTP Banner
I performed the test using the primary domain of a cPanel account that is assigned to a dedicated IP address, different from the main server IP address. The reverse DNS (PTR) record of the account-specific dedicated IP address is not the same as the account domain name nor the server hostname, yet the mxtoolbox web site reports that "Reverse DNS matches SMTP Banner."

The test results lead me to believe that the reverse DNS being compared to the SMTP banner is the actual PTR record of the hostname in the SMTP banner and not the reverse DNS of the unique, dedicated IP address that happens to be used by a hosted cPanel account.

What problem is addressed by changing the existing Exim behavior? Where does this need originate? I ask because I am not aware of any reason why e-mails would be rejected when the SMTP banner correctly reports a hostname that has matching PTR record for its IP address when the connection uses a different IP address, which has its own unique PTR record that is different than the cPanel account domain name.

If the SMTP banner matches only the PTR record of the IP address used in the connection, how does this affect or help add-on and parked domains that share the same IP address as the account primary domain name?
 

markhard

Well-Known Member
Apr 22, 2004
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my setup is like this:

1.1.1.1 hostname.domain.com -> used for all shared accounts

then i setup an account with dedicated IP and set it on /etc/mailips and /etc/mailhelo

2.2.2.2 is dedicated IP for thedomain.net

/etc/mailips:
thedomain.net: 2.2.2.2
*: 1.1.1.1

/etc/mailhelo:
thedomain.net: thedomain.net
*: hostname.domain.com

1.1.1.1 rDNS is set to hostname.domain.com while 2.2.2.2 rDNS is set to themail.thedomain.net

the settings works fine as thedomain.net is sending email with outgoing IP 2.2.2.2 and the other domains is using shared 1.1.1.1

but when i check thedomain.net on MX Lookup Tool - Check your DNS MX Records online - MxToolbox the SMTP banner is still using hostname.domain.com and not themail.thedomain.net (the rDNS of dedicated IP assigned to the domain thedomain.net)

i found a solution here: Exim customization but it require manual modification on exim.conf so the modification will be revert to cpanel default config when cpup run.
 

cPanelDon

cPanel Quality Assurance Analyst
Staff member
Nov 5, 2008
2,544
11
268
Houston, Texas, U.S.A.
cPanel Access Level
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Twitter
i found a solution here: Exim customization but it require manual modification on exim.conf so the modification will be revert to cpanel default config when cpup run.
To retain custom modifications made outside of the Advanced Exim Configuration Editor in WHM, I recommend using the built-in pre and post script hooks that can be used to automatically execute a custom script or other shell commands to re-apply specific customizations (e.g., via a custom patch to exim.conf):
Code:
/scripts/prebuildeximconf
/scripts/postbuildeximconf
Related documentation: