Lani's Study Books

最近遇到一些Sendmail的問題，
認真的研究一下後，發現其實Sendmail也蠻多檢查機制。

Introduction

If you plan to upgrade your sendmail version, go directly to the current release of sendmail (or at least 8.9.3) which has standard FEATUREs included. However, you may read on, because this page and related pages give background informations about the check_* rulesets.
sendmail 8.8 introduced several new rulesets to control who can use your machine to send/relay e-mail and to avoid UBE from well known sites. These are:

check_relay

checking the host name and host address separated by $|. This ruleset is called whenever a client connects via (E)SMTP to the server.

check_mail

for the MAIL command.

check_rcpt

for the RCPT command (used to prevent unauthorized relaying). This ruleset disables all kinds of known relaying tricks (the trick which is tested by ORBS currently (1999-07-14) is fixed since the end of 1997 according to my logs).

check_compat

checking both MAIL and RCPT also separated by $| before delivery.