Found this here: https://kinsta.com/knowledgebase/free-smtp-server/
Abridged Version Below:
Gmail Free SMTP Server Information
Outgoing Mail (SMTP) Server: smtp.gmail.com
Use Authentication: Yes
Use Secure Connection: Yes (this can be TLS or SSL depending on your mail client)
Username: GMail account (firstname.lastname@example.org)
Password: GMail password
Port: 465 or 587
Send and Receive Email in Gmail with Custom Domain
Did you know that you can also send and receive email from custom domains within Gmail? Lots of people juggle multiple business and personal emails in today’s busy world, and consolidating them saves time from having to bounce around a lot. One easy way to do this is to simply use a G Suite email. However, these cost $5 per month. And if you are juggling multiple email addresses this can add up quite fast. We are going to show you a much cheaper solution that you might not have considered.
Lets assume this is your case scenario and you have 4 emails you are trying to juggle:
- 1 personal Gmail account (email@example.com)
- 1 business email account for your WordPress business
- 2 business emails for other websites you run
A lot of times verification for things require that it come from a custom domain. Such as verifying LinkedIn company pages, Pinterest, etc. It also simply looks more professional when you are emailing people from a custom domain.
1. Forward Email To Gmail
The first thing you need to do is forward the email from those 3 additional email accounts to your personal Gmail account (firstname.lastname@example.org). There are a couple ways you can do this. If you have access to your DNS records with your domain registrar, a lot of them now offer free email forwarding. NameCheap is an example of one that does. However, if you are using custom DNS records this option won’t be available. And this is where a 3rd party service like Pobox comes into play.
Pobox allows you to forward up to 40 different addresses for $35 a year. If you were to purchase G Suite for 3 additional emails that would cost you $180 a year.
2. Send Mail As (Google SMTP)
So now that you have all your email accounts forarding mail to your personal Gmail account you need a way to send from those accounts. So within the Gmail settings you can click into “Accounts and Import.” Then click on “Add another email address you own.”
Enter in your additional business name and business email that is on the custom domain.
Then for the SMTP server it will by default show your custom domain. However, you will want to change this to use Google’s free SMTP server. So change it to smtp.gmail.com. Then enter in your personal Gmail address for the username (email@example.com) and your password. This is used for authentication on the SMTP server.
You then can repeat the above steps for your other additional email accounts. And now all your email will come to one place and when you go to send mail you can choose from the drop down which one to send from. In the Gmail settings you can also set the “Reply from the same address the message was sent to” to make it easier when replying to emails.