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Your mail being delayed, read about our greylisting anti spam methodology.

Statistically more than 80% of all email you receive is unsolicited!

On Friday the 3rd of August 2007, Quadra Hosting implemented a new technology across it’s mail servers aimed at stopping the constant stream of spam that is travelling across the internet into our client’s mailboxes.

This technology is known as greylisting which fundamentally operates as follows:

In name, as well as operation, greylisting is related to whitelisting and blacklisting. What happens is that each time a given mailbox receives an email from an unknown mailserver that is trying to send you mail that mail is temporarily rejected with a "try again later"-message.

This, in the short run, means that all mail gets delayed at least until the sender tries again, the sender will retry to send the message without any user intervention.

This is where spam loses out! Most spam is not sent out using RFC compliant MTAs, this means that spam sending software is not following the rules of sending out mail. We know that spam is a numbers game, spamming software will send to thousands of email addresses and it is aware of the fact that not all of them will be reachable, therefore spam software won’t retry sending those that were unable to be delivered.

The mailservers at Quadra Hosting will reject any incoming mail connections from a new source for one minute, a subsequent connection after that one minute period will be accepted and mail will be delivered.

Once this delivery has been made the sender will be placed into a database for 36 days so any further connections will no longer need to wait even that one minute period, with each communication the 36 day period will reset and the source will not be greylisted again and will always be accepted immediately.

We have found that some mailservers are not always handling greylisting well and take a lot longer in retransmitting their mail messages, these mail servers are fundamentally not really in compliance with the recommendations but as they our not within our control there is nothing we can do about that particular occurrence.

People who are experiencing difficulties with greylisting and therefore are experiencing longer then desirable delays now have the option to disable greylisting for their domains.
Please be aware that disabling greylisting will result in effectively also disabling the anti spam system that it provides.

If you prefer to not have greylisting on your domain then please submit a support ticket informing us of the domain(s) for which you want to disable greylisting.
Note these are the domains on which you are receiving email so your own domains, NOT the domains you are receiving email from.

Finally we want to inform you that greylisting is not our final effort in combating spam and we are continuing to look into anti-spam systems that would be of benefit to our clients.

Article Details
Article ID: 141
Created On: 08 Aug 2007 11:51 PM
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