Mailing lists and security against spam

[steveob]

Hi All,

 

I wasn't sure in exactly what area I should post this, if it's in the wrong place I apologize.

I'll just give some quick background, so you can see where I'm coming from.

 

I'm designing a website and mail forwarder for a small local club.

We have affiliations with two other clubs, and some of our members like to receive the newsletters from these clubs via email.

 

Instead of each club trying to maintain a mailing list for our members, we want to make things simpler, and maintain these lists from our end.

 

What I want to achieve:

We need to streamline the process, so that for example an affiliated club can send their newsletter to our club i.e clubmembers@someclub.com.

Then a cron'd php script will check that mailbox for emails from our affiliated clubs, grab the email, grab the list of members that wish to receive those emails, and batch forward them on.

 

The Big Question

Obviously there needs to be some filtering in the process. So if by chance, irrelevant emails arrive in that mailbox, they'll be deleted and not forwarded.

 

How can I achieve this safely? I can check the 'From' field in the headers, but of course they could be manipulated by an ill-meaning person.

 

We're a fairly small club, so malicious spam attacks probably aren't likely. But I want this project to be as solid as possible once I have to hand it over to the club.

 

Any suggestions appreciated.

 

Cheers,

Steve