I am setting up a multi-server system with a separate web server, mail server, etc. On the web server I need to be able to have some type of email service for customers contact forms and such that assume a mail server in on that machine, but I don't want customers emails to go there. What should I install to allow web based programs outgoing email access. Thanks!
As a basis you need a sendmail-compatible program. Any "sendmail" or "postfix" will allow what you want to have, as php mail functions sends mail through the local sendmail binary by default. Be aware that this is not the best way to send mails (you should push clients into using smtp-mail in php, too!) as it can lead to spam being sent through unsecure mail forms and thus your server being blacklisted at mail receivers.
I did install postfix and told it to use smarthost where we have a bounce monitor. Even if you tell your users to use SMTP instead of sendmail a compromised contact form will still allow spammers thru. Thanks!
