Is there any forward / redirection limit in exchange (2016)?

Question

A customer needs a redirection like this:

Mail => [e-mail] => [e-mail] => [e-mail] => [e-mail]

The redirection works until user3 but user4 does not get the mail. When the mail is sent directly to user2 then user4 gets the mail. So there seems to be a redirction limit in exchange 2016 (it seems to be working till exchange 2010).

Is there any limit that can be increased?

Answer 1

There are such limits, and they are even enforced across Exchange servers.

The Microsoft article Exchange Online Limits, lists these limits in section Journal, Transport, and Inbox rule limits (bold emphasis is mine):

Number of times a message is redirected

The number of times a message will be redirected, forwarded, or replied to automatically based on Inbox rules. For example, User A has an Inbox rule that redirects messages to User B, based on the sender. User B has an Inbox rule that forwards messages to User C based on keywords in the subject line. If a message satisfies both of these conditions, the message is only sent to User B; it's not forwarded to User C because only one redirection is allowed. In this case, the message is dropped without sending a non-delivery report (NDR) to User B indicating that the message wasn't delivered to User C. We make use of the X-MS-Exchange-Inbox-Rules-Loop header to determine the number of times that a message was redirected. This header remains also across Exchange organizational boundaries.

There does not seem to be any way of modifying this limit. You are already lucky that you can do two redirections, since the documentation only specifies one.

The article Office 365 Exchange Online Plans (1 / 2 / Kiosk) Differences and Comparison lists this same hard limit for all Office 365 plans (although it dates from 3 years ago and things might have changed).

You may defeat this mechanism if you can find a way to delete the X-MS-Exchange-Inbox-Rules-Loop header from the email while redirecting, but I'm afraid that I can't help you in that.