I have posted similar questions about this, but we are still facing this challenge of using separate SMTP Connectors pertaining to multiple External Smart Hosts
My current on-premises environment is Exchange 2013 DAG; (2 Nodes).
Currently we send all outbound email through Google's Smart Host, (and they provide inbound SPAM filtering for us).
Our dilemma pertains to our process of sending out monthly customer billing email blasts. Google has some restrictions that are inhibiting us from sending the amount of customer emails that we need to send out.
I looked into a 3rd party to use for this, (SMTP.com). This seemed to work for us. However, we couldn't separate out the Send Connectors and thus had to remove Google's external Smart Host as our Send Connector, and just send all of our Outbound Mail through SMTP.com's Send Connector. This was doing the job fine, until we discovered that when our internal employees would set their External Out of Office, but SMTP.com would not relay these messages.
What I'm wondering is this;
Would it be possible to setup a separate E-Mail Server on our LAN, but would be independent from our current Exchange environment, and that separate E-Mail Server would be used for our customer e-mail blasts. We would have that separate E-Mail Server use SMTP.com for it's External SMTP Send Connector, and I could continue to use Google's External SMTP Send Connector for the rest of our E-Mails within Exchange.
I've read a little bit on Split Domain but I'm not sure that would work in this scenario.
Please let me know your thoughts when you have an opportunity.
Thanks.