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Office 365 Domains

Dennis Pillow
Dennis Pillow used Ask the Experts™
I have a 365 E3 account and I have just noticed a domain xxx.onMicrosoft.com
Is this legitimate?
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Top Expert 2016
yes it will be your tenantname.onmicrosoft.com
Alan CoxSr. Architect | Consulting

Yes that is your placeholder domain and is critical for some routing. If you are going to setup hybrid, you'll get another domain in your accepted domain (and will see it in EXOL) domain.mail.onmicrosoft.com. this address is stamped in the on premises user's "target address" attribute so that exchange hybrid (if using) will know how to route mail to users that have migrated to office 365.
Dennis PillowOwner G-Tech Consulting LLC


Thanks for the concise information. I do appreciate your help.