Exchange Online TLS Endpoints POP3/IMAP

In 2020 Exchange Online a TLS1.0 ve TLS1.1 support Microsoft was terminated by.

Microsoft within this year POP3/IMAP4 in TLS1.0 ve TLS1.1 plans to end its support, but when viewed on a global scale, the old TLS There are organizations that actively use their versions. That's why Microsoft eski TLS for organizations using versions of Endpoint created.

Older TLS versions for POP3/IMAP4 will start rejecting connections after February 2023. TLS2023 and TLS1.0 versions will be completely disabled by the end of April 1.1.

POP3/IMAP4 Configuring the Endpoint

Eski TLS For clients that support versions Microsoft's The new Endpoint must be configured as ALL as follows.

  • pop-legacy.office365.com
  • imap-legacy.office365.com

21 VianetOrganizations that use must make the following configuration;

  • pop-legacy.partner.outlook.cn
  • imap-legacy.partner.outlook.cn

AllowLegacyTLSClient The value of the parameter is; $trueSet-TransportConfig must be.

AllowLegacyTLSClient We first connect to EXo to check and change its parameters.

Connect-ExchangeOnline

The command we need to use to query the current status of the parameter is as follows;

Get-TransportConfig | Format-List AllowLegacyTLSClients
Get-TransportConfig

By default, the relevant parameter is Null. If you want to change it to $true, the set to be used is as follows;

Set-TransportConfig -AllowLegacyTLSClients $true 

If you want to grant old TLS access from the new EAC page, we must first log in to the Exchange Online portal as an administrator using the link below.

Message trace – Exchange admin center (microsoft.com)

Mail Flow In the Settings tab “Turn on use of legacy TLS Client” You need to activate the section.

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