• Home
  • About us
  • Contact
  • Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar

Welcome to www.DoitFixit.com

www.doitfixit.com

  • Microsoft
  • Fortinet
  • Symantec
  • Office 365
  • Azure
  • Others
  • Show Search
Hide Search

Reverse DNS does not match SMTP Banner

July 1, 2014 By Damitha Anuradha 1 Comment

www.mxtoolbox.com is a great place to check SMTP settings on your mail server. “Warning – Reverse DNS does not match SMTP Banner” is a common warning message almost every IT person facing. If you are looking to remove this issue you came to the right place. Just follow below steps and you will be able to remove the warning from SMTP checking systems such as Mxtoolbox.

As shown in below image “SMTP Reverse DNS Mismatch” warning is appearing because SMTP connection is looking for “EX01.domain.local” FQDN and which is local FQDN of your messaging system. (In this scenario – Microsoft Exchange Server 2010) Since EX01.domain.local is not a public name it is unable to solve the DNS.

Perform a Telnet to your Exchange server and determine the SMTP banner shown.

telnet mail.domain.com 25

As shown in above session, the banner indicates a local FQDN of your mail host. To change this you have to go to your Internet Receive Connector and change the text of the banner.

To get a list of receive connectors with its name and banner, execute below command in Exchange Management Shell.

Get-ReceiveConnector | fl name,banner

To change the SMTP banner execute below command. <Internet Server Name> should be your internet FQDN of email server.

Set-ReceiveConnector “Default EX01” -Banner “220 <Internet Server Name> <Banner Text>“

Note: The replacement SMTP banner text string must always start with 220. As defined in RFC 2821, the default service ready SMTP response code is 220.

Now perform a MX Lookup and you will no longer getting a “SMTP Reverse DNS Mismatch” warning.

Reader Interactions

Comments

  1. Viktor says

    February 26, 2019 at 3:08 pm

    thank you very much, problem fixed

    Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Primary Sidebar

Recent Posts

  • privacy
  • Veeam Backup – Failed to prepare guests for volume snapshot
  • How to Configure/Integrate FortiClient EMS with FortiAnalyzer
  • Backup Hyper-V Virtual Machines with Pass-Through Disks
  • Slow Network Speed with Hyper-V Virtual Machines on Windows Server Server 2019
  • Block MS Exchange Server OWA access from Internet
  • Error 1168 – The specified product key could not be validated.
  • Unable to Enable Desktop Icons after Joining to the Domain
  • Veritas BackupExec – A backup set was created which contains no data 0xe00084b7
  • Download Offline Address Book – Unexpected Error has occurred

Deprecated: genesis_footer_creds_text is deprecated since version 3.1.0! Use genesis_pre_get_option_footer_text instead. This filter is no longer supported. You can now modify your footer text using the Theme Settings. in /home/wwwdoitf/public_html/wp-includes/functions.php on line 5238