Acceptalladdresses, acceptvalidaddresses Channel Options

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Envelope recipient validity checks (acceptalladdresses, acceptvalidaddresses)

When specified on a source channel, the acceptalladdresses option causes all envelope recipient addresses to be accepted unconditionally. Rather than returning errors during the SMTP session, a delivery status notification, or DSN, will be returned later if the message cannot be delivered to the specified recipient.

In constrast, setting the acceptvalidaddresses option on a source channel causes all envelope recipient addresses to be validated prior to being accepted by the MTA. If an address fails to validate an appropriate error will be returned to the client. acceptvalidaddresses is the default.

The acceptalladdresses channel option is useful when dealing with clients that fail to report SMTP errors correctly to the user. In such cases a DSN, while providing less immediate indication that there's a problem, may be the only way to convey accurate error information to the user.

Unconditional address acceptance should be used with extreme care; in particular, it should never be used on a source channel that accepts unauthenticated transactions from the Internet. The problem with such usage is that spammers will attempt to send mail to invalid addresses, which will be accepted and laster result in a DSN being returned. Since envelope from addresses on spam are commonly forged, this will turn the system into a major source of blowback spam and is likely to result in blacklisting and other operational issues.

These options were first added in JES MS 6.1.