KB Article #176040
Is Office 365 supported by MailGate?
Problem
With Microsoft's Office 365 cloud service gaining popularity recently, there has been increasing number of inquiries whether it is supported by MailGate as a SMTP relay in lieu of the existing in-house mail server solutions.Resolution
While Office 365/Exchange Online is not listed as a supported 3rd party solution in MailGate documentation, MailGate SC can interoperate with email relays and email servers that conform to SMTP (RFC 821 and RFC 1123) or ESMTP (RFC 2821) standards. Since Office 365/Exchange Online will fit in this criteria, we do not foresee any issues, unless there are any unconventional settings required in the implementation of Office 365, in which event, it is highly recommended to share them (or any custom business requirements) with Axway Support, so we can advise whether such migration would be feasible.
If Office 365 is just added as a conventional mail hop on port 25, i.e. to relay email to/from internal domain(s), we do not expect any insuperable issues.
In Axway's experience with customers who already have such implementation deployed, there are usually two key points in the setup:
- Given the nature of mail relaying within Office 365 environment, we have seen issues with a particular MailGate defense mechanism: Loop Detection, which blocks emails with more than N number of received headers (default is 15). In Microsoft's Office 365 environment, mail is often relayed through additional set of relays resulting in email being blocked with a "too many hops" error. The solution is to either disable this MailGate protection (not recommended) or check with Microsoft what would be the maximum possible number of hops in their environment (usually 20 or 25 is sufficient), so that you can adjust the setting appropriately. The latter is recommended, so endless loops are avoided.
- In the Office 365 environment, MailGate must be able to relay email without authentication (the "Anonymous Users" setting must be enabled for MailGate's receive connector in Exchange).