Proxy SMTP Servers

AboutMyXApp SMTP proxy server: http://www.aboutmyip.com/AboutMyXApp/SmtpProxy.jsp

“DeleGate is a multi-purpose application level gateway, or a proxy server which runs on multiple platforms (Unix, Windows, MacOS X and OS/2). DeleGate mediates communication of various protocols (HTTP, FTP, NNTP, SMTP, POP, IMAP, LDAP, Telnet, SOCKS, DNS, etc.), applying cache and conversion for mediated data”