Should email sent from a domain come from the same serves as the MX records?

[EQ Admin]

I was recently asked if email from a domain should be expected to come from the same servers listed in the MX records.

The answer is no.

It is possible and some domains do indeed use the same servers for incoming and outgoing email, but it should not be expected that this is always true or to be expected.

It is perfectly valid to use different email servers and IP addresses for incoming and outgoing email for a domain.