{"id":7616,"date":"2022-01-05T04:36:12","date_gmt":"2022-01-05T04:36:12","guid":{"rendered":"https:\/\/www.insentragroup.com\/us\/?p=7616"},"modified":"2024-09-19T07:43:02","modified_gmt":"2024-09-19T07:43:02","slug":"divestiture-challenge-restricting-messages-and-sending-notifications","status":"publish","type":"post","link":"https:\/\/www.insentragroup.com\/us\/insights\/geek-speak\/migrations\/divestiture-challenge-restricting-messages-and-sending-notifications\/","title":{"rendered":"Divestiture Challenge \u2013 Restricting Messages and Sending Notifications"},"content":{"rendered":"\n<p>While working with a corporation who was <a href=\"https:\/\/www.insentragroup.com\/us\/services\/professional-services\/migrations\/tenant-to-tenant-migrations\/\" target=\"_blank\" rel=\"noreferrer noopener\">divesting a small portion of their business<\/a>, we were presented with an interesting challenge. On the day of signing, the divesting company, known here as \u2018BIGCOMPANY\u2019, would allow users from the divested company, known here as \u2018SMALLCOMPANY\u2019, to retain access to their mailboxes via the Outlook client for retrieving and exporting legacy data, however, did not want any new emails being sent from or delivered to the SMALLCOMPANY mailboxes.<\/p>\n\n\n\n<p>In addition to blocking inbound messages to and outbound messages from SMALLCOMPANY mailboxes, BIGCOMPANY also wanted a method for notifying external senders that the SMALLCOMPANY users\u2019 email address has changed.<\/p>\n\n\n\n<p>To meet BIGCOMPANY\u2019s requirements, we configured a series of the mail flow rules (also known as transport rules) to identify and then act on messages sent to or from SMALLCOMPANY mailboxes.<\/p>\n\n\n\n<p>The objectives of the mail flow rule approach are to:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Block SMALLCOMPANY personnel emails sent from their BIGCOMPANY mailbox from being delivered<\/li><li>Block SMALLCOMPANY personnel from receiving internally and externally generated emails in their BIGCOMPANY mailbox<\/li><li>Notify internal and external senders that the SMALLCOMPANY recipient is no longer receiving mail at their BIGCOMPANY email address<\/li><\/ul>\n\n\n\n<h3 style=\"padding-bottom: 15px;margin-bottom: 30px;margin-top: 40px;border-bottom: 1px solid #F37237;color: #F37237\"><span>ALIGN EMAIL ADDRESS PREFIXES<\/span><\/h3>\n\n\n\n<p>Since we are using a mail flow rule to communicate the email address change, every external sender will receive the same change notification message regardless of which SMALLCOMPANY mailbox they send to. For this reason, we chose to simply notify the external sender to swap the BIGCOMPANY domain name with the SMALLCOMPANY domain name in the user\u2019s email address and then resend the message.<\/p>\n\n\n\n<p><em>For example<\/em>: Alan.Green@BIGCOMPANY.com would become Alan.Green@SMALLCOMPANY.com<\/p>\n\n\n\n<p>In preparation for this \u2018swap\u2019 messaging, we ensured each SMALLCOMPANY mailbox had an email address assigned to it using the local-part (text before the \u2018@\u2019 sign) of the BIGCOMPANY email address.<\/p>\n\n\n\n<h3 style=\"padding-bottom: 15px;margin-bottom: 30px;margin-top: 40px;border-bottom: 1px solid #F37237;color: #F37237\"><span>CREATE DISTRIBUTION GROUP AND ADD MEMBERS<\/span><\/h3>\n\n\n\n<p>In preparation for the mail flow rules to act against a group of mailboxes, a Distribution Group must be created and each of the SMALLCOMPANY mailboxes added as members.<\/p>\n\n\n\n<p><strong>Note<\/strong>:\u00a0\u00a0\u00a0 In Exchange Online, there is no need to create a \u2018Microsoft 365 Group\u2019 for this option. A \u2018Distribution list\u2019 will be sufficient for the mail flow rule<\/p>\n\n\n\n<h3 style=\"padding-bottom: 15px;margin-bottom: 30px;margin-top: 40px;border-bottom: 1px solid #F37237;color: #F37237\"><span>BLOCK SMALLCOMPANY SENT MESSAGES FROM BEING DELIVERED<\/span><\/h3>\n\n\n\n<p>The first mail flow rule will be created to prevent messages sent from SMALLCOMPANY personnel from being delivered.<\/p>\n\n\n\n<p>The mail flow rule will silently drop any email sent from a SMALLCOMPANY mailbox.<\/p>\n\n\n\n<p>The following diagram shows an example of how the mail flow rule would be constructed.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>This rule will apply if (\u2018Apply this rule if\u2026\u2019) the \u2018sender\u2019 is a member of the Distribution Group, \u2018<em>DL Block Internal Message<\/em>\u2019<\/li><li>If the user is a member of the Distribution Group, \u2018<em>DL Block Internal Message<\/em>\u2019, then the rule will \u2018Do the following\u2019 and \u2018Delete the message without notifying anyone\u2019<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"421\" src=\"https:\/\/www.insentragroup.com\/us\/wp-content\/uploads\/sites\/21\/2022\/01\/image-7-1024x421.png\" alt=\"\" class=\"wp-image-7617\" srcset=\"https:\/\/www.insentragroup.com\/us\/wp-content\/uploads\/sites\/21\/2022\/01\/image-7-1024x421.png 1024w, https:\/\/www.insentragroup.com\/us\/wp-content\/uploads\/sites\/21\/2022\/01\/image-7-300x123.png 300w, https:\/\/www.insentragroup.com\/us\/wp-content\/uploads\/sites\/21\/2022\/01\/image-7-768x315.png 768w, https:\/\/www.insentragroup.com\/us\/wp-content\/uploads\/sites\/21\/2022\/01\/image-7.png 1115w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h3 style=\"padding-bottom: 15px;margin-bottom: 30px;margin-top: 40px;border-bottom: 1px solid #F37237;color: #F37237\"><span>BLOCK INTERNAL MESSAGE FROM BEING DELIVERED<\/span><\/h3>\n\n\n\n<p>The second mail flow rule will prevent the SMALLCOMPANY mailbox from receiving internally generated emails. This rule will send a notification to the internal sender stating the SMALLCOMPANY user has moved to a new email address.<\/p>\n\n\n\n<p>The following diagram shows an example of how the mail flow rule would be constructed.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>This rule will apply if (\u2018Apply this rule if\u2026\u2019) \u2018The sender is located\u2019 \u2018Inside the organization\u2019 and \u2018The recipient is a member of\u2026\u2019 the Distribution Group, \u2018<em>DL Block Internal Message<\/em>\u2019<\/li><li>If the above conditions are met, then the rule will \u2018Do the following\u2019 and \u2018Reject the message with an explanation\u2026\u2019. The verbiage for the email address change notification will be added to this action<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"447\" src=\"https:\/\/www.insentragroup.com\/us\/wp-content\/uploads\/sites\/21\/2022\/01\/image-8-1024x447.png\" alt=\"\" class=\"wp-image-7618\" srcset=\"https:\/\/www.insentragroup.com\/us\/wp-content\/uploads\/sites\/21\/2022\/01\/image-8-1024x447.png 1024w, https:\/\/www.insentragroup.com\/us\/wp-content\/uploads\/sites\/21\/2022\/01\/image-8-300x131.png 300w, https:\/\/www.insentragroup.com\/us\/wp-content\/uploads\/sites\/21\/2022\/01\/image-8-768x336.png 768w, https:\/\/www.insentragroup.com\/us\/wp-content\/uploads\/sites\/21\/2022\/01\/image-8.png 1110w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>You can learn how to plan for tenant migrations in mergers, acquisitions and divestitures in <a href=\"https:\/\/www.insentragroup.com\/us\/insights\/geek-speak\/migrations\/how-to-prepare-for-microsoft-365-tenant-to-tenant-migration-and-consolidation-projects\/\" target=\"_blank\" rel=\"noreferrer noopener\">this previous article<\/a>.<\/p>\n\n\n\n<p>References:<\/p>\n\n\n\n<p>Mail flow rules (transport rules) in Exchange Online:<\/p>\n\n\n\n<p><a href=\"https:\/\/docs.microsoft.com\/en-us\/exchange\/security-and-compliance\/mail-flow-rules\/mail-flow-rules\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/docs.microsoft.com\/en-us\/exchange\/security-and-compliance\/mail-flow-rules\/mail-flow-rules<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>While working with a corporation who was divesting a small portion of their business<\/p>\n","protected":false},"author":117,"featured_media":7621,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"content-type":"","footnotes":""},"categories":[22],"tags":[246,244,243,83,245,60,247,208],"class_list":["post-7616","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-migrations","tag-ad-migrations","tag-divestiture","tag-email-migration","tag-exchange-online","tag-mailbox-migration","tag-microsoft-365","tag-outlook","tag-tenant-migration","entry"],"_links":{"self":[{"href":"https:\/\/www.insentragroup.com\/us\/wp-json\/wp\/v2\/posts\/7616","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.insentragroup.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.insentragroup.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.insentragroup.com\/us\/wp-json\/wp\/v2\/users\/117"}],"replies":[{"embeddable":true,"href":"https:\/\/www.insentragroup.com\/us\/wp-json\/wp\/v2\/comments?post=7616"}],"version-history":[{"count":3,"href":"https:\/\/www.insentragroup.com\/us\/wp-json\/wp\/v2\/posts\/7616\/revisions"}],"predecessor-version":[{"id":8901,"href":"https:\/\/www.insentragroup.com\/us\/wp-json\/wp\/v2\/posts\/7616\/revisions\/8901"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.insentragroup.com\/us\/wp-json\/wp\/v2\/media\/7621"}],"wp:attachment":[{"href":"https:\/\/www.insentragroup.com\/us\/wp-json\/wp\/v2\/media?parent=7616"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.insentragroup.com\/us\/wp-json\/wp\/v2\/categories?post=7616"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.insentragroup.com\/us\/wp-json\/wp\/v2\/tags?post=7616"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}