Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Having problems with the default e-mail provided by a shared host (blacklisting and quotas), so I'm looking into SMTP services to handle outbound mail instead.

However, one thing that I haven't been able to figure out about the setup is how mail sent through the service would preserve the authenticity of the original domain... bad wording, but I'll explain. If I'm sending e-mails directly from the office network to the SMTP service, without relaying it first through the shared host (to which the domain name is registered), will I not see mail bouncing back because the domain and IP don't match?

I figure I need to do something along the lines of adding an MX entry to my domain, but to my knowledge, that only applies to incoming mail. Something through the registrar, maybe?

Any corrections / suggestions are much appreciated. E-mail protocol isn't something I've read much on... yet.

share|improve this question
I think I'm trying to figure out the same problem as you but no solution yet. – Nicolas Manzini Jun 4 '13 at 0:42
up vote 0 down vote accepted

The best solution would be to use your MX mail server as a relay for your office network. Due to the very diverse methods of spam protection used by different hosts, this is the most reliable way to prevent your mails from being spam filtered. If however the offical SMTP server for your domain is often blacklisted because it is on a bad shared hosting service, you will need to move it away from there as you will always have trouble to send mail and just sending the mails form your office network will not help with it all that much.

Other than that, you could look into SPF and/or DKIM to associate your office network with your mail domain, which is good idea to adapt for your MX host anyway. Both methods use special DNS records to indicate which hosts are allowed to send mail on behalf of a specific domain, with DKIM the more advanced and reliable but considerable more difficult method. However, if your office network is connected to the internet via some kind of dial-up network (e.g. DSL), it might very well be that this network range is blacklisted as such in some database and many hosts will flatly refuse to talk to your office network hosts, SPF/DKIM or not. Use this service to check. There is nothing you can do about this except relay mail through your official mail server.

share|improve this answer
Alrighty. Now, at least, I know where to start tackling this. Thanks! – Dan Anderson Jun 4 '13 at 2:21

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.