Arrow Technology Anti-spam Systems

Every Arrow Technology email server has two anti-spam systems.

The first system blocks spam mostly by using block lists, which are commonly used lists which are mantained by various organisations. Many spammers will get detected when they spam fron specific computers and get added to these block lists.

Bear in mind that spammers often infect other peoples computers, so sometimes legitimate email servers might be blocked if they are sending spam. If a computer is a prolific spammer, they will stay on the block list for a very long time or permanently, but many computers subsequently stop sending spam and might be unlikely in as little as just a few hours.

That first system will also block some 'legitimate' email servers that have been incorrectly configured. Unfortunately these badly configured email servers look exactly like spammers. There are a few of these around and surprisingly some are unwittingly even used by larger organisations where their IT and service providers are either unaware or don't care. Probably the organisations would care, but they don't know.

We do not see huge numbers of these bad servers compared with the number of correctly configured email servers, but they do crop up fairly regularly. This is absolutely a problem with the sending email server and those servers should be fixed; the causes and fixes are welll documented and easy to demonstrate. We have an auto-whitelisting feature that significantly alleviates the problem and yet still allows us to block lots of spammers.

Anyone that sends an email that is blocked by this first anti-spam system should receive a bounce/non-delivery notification from their own email server, because the checking is done before the email is accepted for delivery and therefore the sending email server can be given the notification.

The second anti-spam system is based more on the content of the message, is a more involved analysis and tends to be very accurate; it very rarely blocks legitimate emails. It also supports a good level of customisation of the checking process.

Arrow Technology actively maintains a centralised list our own rules which are then automatically distributed to all of our email servers. Spams vary over time and there are often specific messages that appear regular at any one time. We analyse common spam messages and use our rules to assist with blocking them.

Anyone that sends an email that is blocked the second anti-spam system may not receive a non-delivery notification, because the checking is done after the email has been accepted for delivery. That means the sending email server has already gone before the reason for rejecting the email is known, so the sending server cannot be told about it.

 

Unfortunately with spam rates being so high and many spams attempting to look like legitimate emails, it is impossible to stop all of them. If you are using our email services you will probably receive some spam messages, but hopefully not many.

Bear in mind that you can call or email us to discuss any specific email issues. Email services are very important and we will assist with discovering any issues with emails that you either send or receive (or did not receive).

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