TJINFO

greylist

Another method of stopping spam

You are probably reading this page since you got this error message:

  421-Nice to meet you - please try again in 3 minutes
  421-For more information see: http://tjinfo.uib.no/greylist.html
  421 or contact postmaster@uib.no

Nowadays most spam is sent from infected home PCs in private homes. The spambots running on a PC do not have any logic for resending a failed message, these applications appear to adopt the "fire-and-forget" methodology. A decent mail server however, will try to deliver a message for at least 3 days.

Mail is transfered between mail servers using the protocol SMTP, defined in RFC2821. During delivery the receiving server will respond with three-digit codes:

While a real mail server will retry after the reception of a 421-message, spammers will not!

Current configuration at the University of Bergen will reject a message the first time it is seen. After 3 minutes a message from the same sender and host to a local user in Bergen will be accepted. After this reception all further mails will be accepted with no further delay.

If you are receiving this error while sending mail to the University of Bergen your mail server is broken and you should contact your support personal demanding the server to be upgraded so that it is conforming to the Internet standards. When a 421 reply is received, your server should requeue the mail and retry after some time. At the University of Bergen a message will be retried for five days untill it is returned to the sender.

If you still have problems reaching students or employed at the University of Bergen, your mail to postmaster@uib.no will be accepted. We will respond to such mails by whitelisting your server so that this test will not be run on your further deliveries.

For more information about greylisting, please look at puremagic.

Tiden ved Universitetet i Bergen er nå 05:43:34 23/9-2017 (+0200)

Du bruker Internet-nummeret 54.198.247.44

Nummeret er i DNS registrert med navnet ec2-54-198-247-44.compute-1.amazonaws.com.

Du er ikke koblet opp via Universitetet i Bergens nettverk.

Sist oppdatert 23/1-2004 av hmk


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©2009 Universitetet i Bergen | IT-avdelingen

Adresse: Postboks 7800 5020 Bergen

Besøksadresse: Nygårdsgaten 5

Telefon: (+47) 55584201

Ansvarlig redaktør: IT-direktøren

Kontakt: hmk



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