outlook 2019 HELO FQDN

Question

Hi.

Lately my SMTP provider is requiring that clients send the helo/ehlo with their FQDN.

I use outlook 2019 on windows 10 and it seems that the HELO/EHLO command uses the computer hostname as input. This is not a FQDN and afaik cannot be set as one. In fact I tried editing its value from the registy (Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Hostname) to a FQDN but this gets reset to a value without periods.

Is there a way to solve this issue apart from asking my ISP to change the setup of their SMTP server.

Answer 1

Hi @Ronald Cordina ,

According to my search, your HELO/EHLO name should be the system's fully-qualified domain name.

Here is an article for your reference: What exactly should HELO say?

(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)

In addition, HELO/EHLO is more related with mail server and that the Outlook tag here we mainly focus on general issues about Outlook desktop client, it is recommended you reach out to your SMTP provider for assistance.

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