Forum Discussion
DrFMS
Apr 13, 2020Copper Contributor
Open Specific External Domain for sending to blocked DLs
I'm looking for a solution to open an External domain to have the ability to send to Distribution Lists, which are blocked for External domains. I know we can do this, via a Transport Rule that targets the specific DLs; however, we have over 12,000 DLs and cannot add them all into a single Transport Rule. Is there a way, in Exchange Online, to tag a specific external domain (without adding it as an Accepted domain) as "Internal", so it can send to these blocked DLs?
Thank you for your time!
- Victor_IvanidzeBronze Contributor
Hi DrFMS,
1) could you please explain in details how can you do that:
"via a Transport Rule that targets the specific DLs" ?
2) > Is there a way, in Exchange Online, to tag a specific external domain (without adding it as an Accepted >domain) as "Internal", so it can send to these blocked DLs?
No way to tag as far as I know.
The only way I see is using of combination of a transport rule and a custom Power Automate flow.
- DrFMSCopper Contributor
Victor_Ivanidze The Transport Rule method we're using is basically this:
Apply this rule if - The To or CC box contains... <all of the targeted DLs>
Do the following... Reject the message with the explanation... <This is an Internal Distribution List>
Except if... The sender's domain is ... <specified domain - primary domain of o365 Tenant>
- Victor_IvanidzeBronze Contributor
Hi DrFMS,
ok, understood.
Q1. do you have the DLs that should behave differently? In other words, can I assume that each your DL should reject external messages with exceptions?
Q2. if the list of external domains that can deliver to your DLs is the same for all DLs or different DLs have different lists of exceptions?