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Greylisting defers all emails from Office 365 accounts

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Kuzma Ivanov
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Applicable to:

  • Plesk for Linux

Symptoms

  • Messages from Office365 mail accounts get deferred by greylisting handler with the following error in /var/log/maillog:

    CONFIG_TEXT: /usr/lib64/plesk-9.0/psa-pc-remote[956]: DEFER during call 'grey' handler
    /usr/lib64/plesk-9.0/psa-pc-remote[956]: Message aborted.
    postfix/smtpd[2028]: 61AF6E27BAB4: milter-reject: DATA from mail-*.outbound.protection.outlook.com[10.10.10.10]: 451 4.7.1 Service unavailable - try again later; from=<user1@officeaccount.com> to=<user2@pleskaccount.com> proto=ESMTP helo=<*.outbound.protection.outlook.com>

    OR

    CONFIG_TEXT: server postfix/cleanup[17368]: C860512160C: milter-reject: END-OF-MESSAGE from mail-eopbgr60135.outbound.protection.outlook.com[40.107.6.135]: 4.7.24 SPF validation error.; from=user1@officeaccount.com to=user2@pleskaccount.com proto=ESMTP helo=<EUR01-DB5-obe.outbound.protection.outlook.com>

  • In some cases email messages are delivered within 1-2 days.

  • The following message can be delivered to a sender (Office365 mail account):

    PLESK_INFO: Final-recipient: RFC822; 1@pleskaccount.com
    Action: failed
    Status: 5.4.0
    X-Supplementary-Info: < #5.4.300 smtp;550 5.4.300 Message expired -> 451 4.7.1 Service unavailable - try again later>

Cause

Emails from *protection.outlook.com are sent from multiple IP addresses. This causes greylisting treat every new retry as a new message, so there is a delay in message delivery until the same pair of email/IP address is logged.

Resolution

If greylisting is enabled at Plesk > Tools & Settings > Spam Filter, set up a server-wide white list for Office 365 domains - a list of hosts which emails will be accepted without greylisting check-ups:

1. Connect to a Plesk server via SSH.

2. Run the command:

# /usr/local/psa/bin/grey_listing -u -domains-whitelist add:*outbound.protection.outlook.com

For more information about configuring greylisting, see:

Additionally, check the following Microsoft TechNet article and make sure that the network allows connections from Exchange Online Protection (EOP) IP address ranges.

Comments

2 comments

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    Fouad Ahmed Fouad

    I didn't use Greylisting for this issue, it's not Outlook domains only what use many ip addresses, it's all major companies like Google and other major hosting companies.

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  • Avatar
    Pavel Mikhaylov

    Hello, Fouad Ahmed Fouad,

    The article addresses a particular issue related to greylisting and Office 365 services.

    In case you are experiencing an issue with different symptoms and the information from our knowledge base does not help, please create a request to our Support team: https://support.plesk.com/hc/en-us/articles/213608509

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