Hello, Apropose greylisting.
On Mon, 23 Jun 2008, Arun Khan wrote:
> Not sure if this 'Net legend but I have heard that some spam software
> take this technique into account and retry the MTA at which point the
> email is accepted.
The principle behind greylisting is that the SMTP RFC allows for:
a. temporary unavailability of resources on the mail server.
b. certain time delays in responses from the mail server.
So the server maintains a record of known transactions in the form
sender A -> recipient B.
If a new mail arrives and is *not* one of these known transactions,
then the delays as above are applied.
So a spambot that is willing to send messages slowly *can* get
messages through such greylisting technique.
Suppose that such a spambot is actually a virus. Due to the near
exponential spread of the virus, there is no need for it to be
"fast".
So, if a virus-writer knows about grey-listing and is willing to
patiently create a bot-net, greylisting _alone_ would be ineffective.
Regards,
Kapil.
--
signature.asc
Description: Digital signature
_______________________________________________ To unsubscribe, email [EMAIL PROTECTED] with "unsubscribe <password> <address>" in the subject or body of the message. http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
