Rate limit enevelope sender out of office

[jape0002_]

Hi!
We have setup rate limit for envelope senders. But we have an issue when people enable their out of office in Exchange. Then a storm of "<>"-senders will be going out and then the "out of office"-messages for all users will be rate limited. 

Is there any way to exclude the blank sender from rate limit envelopesender?

[Mathew Huynh]

Hey Jape,

This is possible to have addresses be exempted from envelope sender rate limiting via the address list and deploying it on the mail flow policy in question, a null <> value cannot be added.

Are these out of office emails coming from internal source? if so perhaps (if this applies to your environment) you disable envelope sender rate limiting on a RELAY host.

If this is for out of office emails coming from the internet into the ESA, then creating that hole could be considered risky as it opens you up to bounce storms if Bounce verification isn't it.

An alternative means for incoming mails would be to use message filters and use the High Volume Email filter rules but it may get convoluted and complicated for the requirement.

Regards,
Mathew