I want to send a bunch of E-Mails to different recipients. My sending server (
myserver.com) ist set up correctly, i.e.:
1. EHLO command, hostname and A DNS record do match 2. PTR record matches hostname and A record
The E-Mails I send are for a 3rd party. Thus, the "mail form:" should include a domain which I don't have access to (
firstname.lastname@example.org). With my understanding, this should not be a problem as long as the "envelope from:" sender corresponds to my sending server, i.e.
Also, I would have to account for any SPF entries in the DNS records of
other.com does not specify and SPF entry this should be fine as well.
Now: Is there anything wrong with this approach? Are there receiving servers which would not deliver my E-Mail? Is there an increased probability that my E-Mails will be marked as spam?
I ask this, because so far from a technical standpoint I don't see any problems with this procedure. On the other hand, it seems that this would make it far too easy to "fake" E-Mails. So this gives me some doubt. Still, this shows why it is important to use an SPF entry, I guess.