Will adding an MX record for email forwarding conflict with an email provider like sendgrid

Question

I'm planning on receiving email/forwarding email using postfix, but sending email using sendgrid.

According to this tutorial, I need an MX record pointing to my machine - http://www.andreagrandi.it/2014/08/31/getting-started-with-digital-ocean-vps-configuring-dns-and-postfix-for-email-forwarding/

I've already set up sendgrid, and its working -> i sent a test email from ibrahim@mysubdomain.domain.com. I did this with no change to my DNS.

My question is, when I set up the MX for email forwarding, will sendgrid stop working?

From what I'm reading, I need an MX record saying sendgrid is a valid sender. But today, sendgrid is able to send, without me doing any DNS change.

I would "just try it" but its my first time with email, and the blacklists make me paranoid.

I've read other answers on mail setup, but I haven't seen one with a different setup for sending and receiving.

Answer 1

From what I'm reading, I need an MX record saying sendgrid is a valid sender. But today, sendgrid is able to send, without me doing any DNS change.

No, it doesn't need to. Instead of MX record, you need SPF.

• MX record was used when handling incoming email i.e. guide the email intended to your domain so it get into your server.
• SPF was used when handling outgoing email, i.e. list all email server who allowed to send behalf your domain.

Answer 2

I found an answer from stackoverflow.

https://stackoverflow.com/questions/17520514/sending-emails-from-my-domain-with-sendgrid

First and foremost, the MX records for your domain are used only to specify the hostnames of the servers to handle INCOMING mail for your domain - i.e. the MX records have nothing to do with the servers that are used to send outgoing mail