測試自己的郵件服務器是不是允許轉發（Open Relay)

一般都是用手工去telnet 郵件服務器 25，來進行交互測試。不過現在有個網址可以幫我進行測試：

http://www.abuse.net/relay.html

只要輸入您郵件服務器的ip地址，它就會自動進行4次以上的測試，最後得出結論，諸如：

THIS MAY OR MAY NOT MEAN THAT IT'S AN OPEN RELAY.

Some systems appear to accept relay mail, but then reject messages internally rather than delivering them, but you cannot tell at this point whether the message will be relayed or not.

You cannot tell if it is really an open relay without sending a test message; this anonymous user test DID NOT send a test message.