Email greylisting: Difference between revisions
imported>Meg Taylor No edit summary |
imported>David MacQuigg (add notes on reliability) |
||
| Line 5: | Line 5: | ||
On the other hand, a delay will always give more time for new sources to be blacklisted. | On the other hand, a delay will always give more time for new sources to be blacklisted. | ||
Greylisting may result in loss of legitimate mail if: | |||
a) The transmitter's retry time is not within the minimum and maximum allowed by the greylisting receiver. | |||
b) The retry comes from a different IP address, causing the receiver to not recognize it as a retry. Retry from a different IP is most likely with large organizations that use multiple transmitters. | |||
Revision as of 05:38, 3 November 2013
Greylisting involves returning a temporary reject on the theory that only legitimate transmitters will retry after a temporary failure.
Greylisting is controversial as to its long-term effectiveness. If enough spam transmitters add retry capability, greylisting will be like a partially-effective anti-biotic. The pathogen population will mutate to a more resistant form.
On the other hand, a delay will always give more time for new sources to be blacklisted.
Greylisting may result in loss of legitimate mail if:
a) The transmitter's retry time is not within the minimum and maximum allowed by the greylisting receiver.
b) The retry comes from a different IP address, causing the receiver to not recognize it as a retry. Retry from a different IP is most likely with large organizations that use multiple transmitters.