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— | faq:email07 [2011/04/30 17:08] (current) – created clemens | ||
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+ | [07] WHAT IS GREYLISTING? | ||
+ | SPAM that you receive can be forwarded to ' | ||
+ | This file is accessible to all users and the purpose of it is to help | ||
+ | | ||
+ | |||
+ | WHAT IS GREYLISTING? | ||
+ | |||
+ | | ||
+ | SDF SMTP server to keep track of the SMTP servers that communicate with it. | ||
+ | When SDF receives a connection from an unknown SMTP server it issues a 451, | ||
+ | which basically means " | ||
+ | | ||
+ | The user is over quota, the file system is full, the load average is too | ||
+ | high and so on. A properly configured MTA will follow the SMTP protocol | ||
+ | and respect a 451 by using its default retry interval which can be | ||
+ | | ||
+ | only in effect for 3 minutes from the sending server' | ||
+ | is well within a reasonable retry period of a properly configured SMTP | ||
+ | | ||
+ | hours of its first attempt, SDF accepts its connection and allows the | ||
+ | email to be delivered. | ||
+ | also takes in account for other SMTP servers on the same network since | ||
+ | | ||
+ | the host number is ignored. | ||
+ | mail harvesting farms such as Gmail. | ||
+ | |||
+ | | ||
+ | being deferred. | ||
+ | |||
+ | You will be able to see the header line X-Greylisting in your email | ||
+ | which will provide you details on the host and perhaps can help you | ||
+ | with any additional filtering you might need. | ||
+ | |||
+ | There is a simple utility called ' | ||
+ | apply to you. Its important to note that if you do see a tuple in the | ||
+ | | ||
+ | | ||
+ | is possible that a spam host could resend before they change their IP | ||
+ | | ||
+ | that they will retry and therefore you will always receive legitimate | ||
+ | email with a very low percentage of that possibly being spam. | ||
+ | |||
+ | By default greylisting is enabled for all SDF members. | ||
+ | like to disable it, which is not recommended, | ||
+ | ' | ||
+ | |||
+ | | ||
+ | own rules to apply to mail delivery specific to their email addresses and | ||
+ | their domains. | ||
+ | no need for a whitelist. | ||
+ | .wl in the user's home directory with a single email address on each row | ||
+ | of the file. The file can only contain email addresses and | ||
+ | | ||
+ | </ | ||
+ | |||
+ | [[email|back]] |