How to send emails for our clients with multiple domains so that reply goes to our clients?

Question

I am planning to do an email marketing as a service to our existing clients. We service mortgage and real estate agents and we do mailings to consumers on behalf of LO and agents. What I would like to do is to hide our domain name and show consumer as the email came from their sales agent/Loan Officer. I am not planning to use 3rd party email marketing services. I talked to a vendor and they told me to achieve what I want I have to create around 7000 sub-domains and then I can send email. agent email is L@mail1.com recipient is b@recp.com our email is c@sender.com

The work flow process has to be like this

b@recp.com will receive an email from L@mail1.com but technically it was mailed from c@sender.com( our office) Please give me some ideas on how to do this?

Answer 1

It sounds like your agents already have their own e-Mail addresses.

If you run your own e-Mail server, you can specify the From, Reply-To, and Return-Path headers to anything you like. Anything more can be handled by the script you use to send the e-Mail.

The main issue will be if any of your agents have SPF records configured for their mail servers. If this is the case, some recipients will likely deny the e-Mail if you change the envelope sender. (Return-Path header) In this case, you could have the Return-Path be an e-Mail address that does not have SPF records or that has SPF records configured for the sending SMTP server.

Another potential solution would be to setup e-Mail aliases for all your agents and forward them to their existing addresses.