'vthrottle' is an implementation of an SMTP throttling engine for Sendmail. It lets sysadmins control how much email users and hosts may send, hindering the rapid spread of viruses, worms, and spam. Exceptions can be made via a whitelist mechanism, which can be generated manually or with the included tool 'vmeasure'. 'vthrottle' tells the misbehaving client to hold on to the deferred mail and resend it later. 'vthrottle' evaluates mail transactions at the connection, the HELO (or EHLO) statement, and the stated source address of the mail. For each of these, a list is traversed and the observed time interval between observations is evaluated. If the observed interval is shorter than the policy interval, the mail is blocked by sending a failure reply code to the SMTP client; the message is then queued. Because 'vthrottle' uses libmilter, it will not work with other MTAs, only with sendmail.
released on 2 June 2004
|License||Verified by||Verified on||Notes|
|BSD 3Clause||Janet Casey||2 June 2004|
Leaders and contributors
Resources and communication
|Required to use||sendmail|
|Required to use||pthreads|
|Required to use||libmilter|
This entry (in part or in whole) was last reviewed on 2 June 2004.