PHP Verify Mail designed to partially prevent automatic/manual registrations based on entering invalid email like user@unexiste.nt which is regexp-valid but not correct. It checks DNS records to ensure domain & MX ok. Same as "phpvmail" project.
A simple Milter which checks the senders and recipients email address are valid (i.e. a MX server will accept mail for it).
Written in PERL using the Sendmail::Milter interface, this caching milter signifcantly reduces the ammount of UCE/UBE.
a public email form writen in php with template design ... file transfers, session support, XHTML compient with default templates, selectable to addresses AND hidden true email addresses, MX record checking for false email addresses
Antispam, antivirus, authenticating SMTP daemon. Integrates with qmail, sendmail, stunnel, etc. It's simple Perl, so you can hack it to suit your needs. Supports RBLs, mx on from, bounce evil phrases, virus scanning...