Make Exchange 2016 detect keyword in subject or body of incoming E-mail and bcc E-mail to a second internal recipient. Rule already in place and working for outgoing E-mail.

you will need to select the option if the sender is outside you organization. it will be a separate rule though. select that option and then add your other actions.

I missed it..... you must first choose "The sender is located....."   then select "Outside the organization"   I added it a new rule then sent two incoming E-mails from Yahoo, one with "scarecrow" in the subject, the other with it in the body.   Received them both but they didn't bcc to the second recipient.  I went back to the rule and noticed (shown in the attachment) that if you hit the drop down after "The sender is located" you see additional choices before the "Outside the organization" URL.   I selected "is external / internal" which didn't work.  I'll try a couple of other options and see if I can get it working.
Exchange-2016-mail-flow-rule.docx

One note on these kinds of things and you may already be fine / aware of this or have it covered ...

Even though something is technically possible, depending on law and why you are doing this, you may need to issue a policy / cover yourself legally before you put this in production. If it is simply to relay production-related information to someone else when it is sent (and you are forgiving a lapse in human communication) that is one thing; but if it is HR / personnel-related, that's were the legality may come into play.

Great point.  The request came from our legal department.  I'll quiz them to ensure they covered all of their bases.   Thanks David

The rule looks good, but try to move the rule up to priority 1 so that other rules don't interfere first.

I deleted and recreated the rule, bumped it up to priority 1, disabled the existing priority 0 rule, sent a test message to "fred smith" (my imaginary friend / test account) which worked fine, then sent an incoming E-mail from my Yahoo account to my account with the word scarecrow in the body.   Once again I received it by poor Fred was neglected.  I also checked his junk mail.    Is it necessary to restart a transport or other Exchange service?

no you don't have to restart any services. instead of selecting subject or body includes, they selecting is subject or body has text pattern. I'm not in front of the console so speaking from memory.

try selecting if subject or body has a text pattern.

No Love with "the subject or body matches these text patterns".  All come through to the primary but the secondary bcc doesn't make it.
Exchange-2016-mail-flow-rule.docx

that looks good. that should be all it takes. I will try to set this up and see what happens.

I'll work with it at home this evening as well.  Thanks for the assist.

I just tested this and it worked fine. I tested with the word in the subject alone, and i tested with the word in the body and both worked just fine and my other email account was bcc'ed. I sent from my external gmail account. see the rule i setup

Test Bcc Rule

If the message...Includes these words in the message subject or body: 'Advance'
and Is received from 'Outside the organization'

Do the following...Blind carbon copy(Bcc) the message to 'Support@myemaildomain.com'

Rule comments

Rule modeEnforce

Even if I take the keyword portion out so the rule simply bccs' a second recipient (also tried redirect to another recipient) it doesn't work.  I'm going to explore two possible causes.
1.  We utilize Mimecast cloud based security which touches every E-mail before delivering it to our organization.  
2.  We are in coexistence mode w/ Exchange.  All the mailboxes have been migrated from 2007 - 2016, we only need to finish archiving and removing old public folders before completing the migration and decommissioning Exchange 2007.  As it stands now, mail flow is and has been working fine in coexistence with the exception of this mail flow rule I am attempting to get working.  Again, the internal mailflow rule works fine, it is only the rule to capture external E-mails.

I'm also in Co-Existence with 2010 and 2016, along with a hybrid setup for O365 but it worked perfectly for me. Currently migrating mailboxes from 2010 to 2016 with O365 hosted archive.

Try adding the trigger word with other words in the subject or body. Don't send the test email with just 1 single word in either the subject or the body.

If I take the keyword condition completely out of the mix and my only condition is -the sender is located.... outside the organization It doesn't bcc.  with the same single condition in place I changed the action  from bcc to redirect the message and entered two mailboxes for the recipients.

In both cases, the E-mail came through to the intended, 1st named recipient and was completely unphased by the rule in place.   So now maybe I should focus my attention on Mimecast.

Agreed.

Attached is the only rule I have active.   No go.  Stumped,  will call Mimecast and may be able to create the rule there.
Exchange-2016-mail-flow-rule.docx

Agreed, check to see if they are interfering because it works perfectly for me with the rule I created:

Test Bcc Rule

If the message...Includes these words in the message subject or body: 'Advance'
and Is received from 'Outside the organization'

Do the following...Blind carbon copy(Bcc) the message to 'Support@myemaildomain.com'

Rule comments

Rule modeEnforce
Report Comment

Hey Tim,  In your working rule,  can you give me the condition line(s) you were using in addition to ""The sender is located outside of the organization"?

Thanks to timgreen7077 for the assist and getting us pointed in the right direction.   The mail flow rules are pretty simple to construct but in our case didn't work by adding the condition "when the sender is located outside of the organization".  We had to add a second condition "when the recipient is located inside of the organization"  Maybe something that changed with a cumulative update?   Working now though.