sending mail for other domains


I am creating something that will be used by organizations to let people make reservations. There are invoice reminders and stuff and now I want to implement something like mass mailing to all people who made a reservation. I set the "from" address to their email, but I am not sure if that is a good thing to do.

Can I get away with this or should I use my own domain (which has everything set up correctly (MX, SPF) as the "from" and their address as the "reply-to"? Or is their another way?

Just want to be sure all messages get delivered but people will not start replying to me…

Thanks for any help,


Yes you should setup your own domain with DNS and so on. I guess otherwise you run into trouble.

It’s perfectly fine to set a custom From header in sent emails. No need to set up anything in DNS as your user’s email address should already work.

Edit: The only problem i could think of is that your SMTP server does some rewriting. Like only allowing local mail domains in the From header.

Thanks for the replies.

I think what you say is true Mike, because I opened one of the emails sent by an organization in raw source and saw:

Received: from


Received-SPF: pass

Looks good to me also…



Right. Changing the Return-Path is another issue. Many SMTP server don’t allow that. For sendmail you have to e.g. add the user under which the webserver is running to trusted-users.

I was thinking about that. Changing it to something which I monitor. Thing is that I use Google Apps to host my mail. i am not sure what would happen if the return path is set to a user/alias over there (like

Makes me think about another issue I have. In my site users need to verify their email address. Someone created an account with (so a missing ‘t’ in the hotmail), so this verification mail never arrived, resulting in a lot of confusing communication.

I know you can set an option in CEmailValidator to check the MX records, but I read somewhere that it is not necessary for mailservers to have this set. Is this true? If so, is there another way of checking whether the email address entered is pointing to a real mailserver?

Short answer: No. That’s why sending validation emails is still the method of choice to make sure, an email is correct. You can of course check, wether there’s a mailserver for a domain. But that doesn’t tell you much.

Thanks. Have to create a nice FAQ then :)