How can I whitelist my mx server in O365?


I'm in process to migrate my users mailboxes from Exchange 2007 to O365.

I set a Send Connector rule to send all emails for migrated recipients to O365 MX server. Now  I got a msg from O365 like: #550 5.7.1 Service unavailable, Client host [x.x.x.x] blocked using Spamhaus. To request removal from this list see

Why my Hub Transport is considered as spam? How can I whitelist my server in O365?

Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Shreedhar EtteCommented:
Hi Sam,

Which migration approach you are using?
Vasil Michev (MVP)Commented:
The blacklist is not with Microsoft but with Spamhaus, as the message above shows. That's where you should unlist it and potentially get an answer why it was blocked.
Saif ShaikhServer engineer Commented:
After removing the exchange server public IP from blacklist you may update the SPF record with exchange server public IP and also include O365 SPF record i.e.

v=spf1 a mx a: ip4: -all

Also you can go to connection filtering in O365 and white-list exchange server public IP.

Sign into Office 365 and click "Admin", then "Admin Centers", followed by "Exchange"
Under the "Protection" list, choose "Connection Filter"
Click the "Edit" button which looks like a pencil
Choose "Connection Filtering" on the left side menu
Click the plus "+" symbol and add an IP range from the list below and click "OK"
Repeat step 5 until the IP ranges below have been entered
Check the "Enable Safe List" checkbox
Finally, click "Save"

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
SAM2009Author Commented:
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.