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Taking care of email delivery

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Nobody likes receiving spam, yet it accounts for over 50% of all email.  As such, spam filtering has become big business.  We use a combination of RBL, firewall rules and heuristics to help prevent spam in your inbox.  We’ve recently been further developing our email delivery systems to ensure your sent mail arrives at its destination.

Historically, each server would deal with its own email.  This seems like a good idea as spam from one server won’t affect another, so problems are less likely.  As each server sends a relatively small amount of mail, the trust needed to enable successful delivery to big providers like hotmail, gmail etc was proving difficult to build.  Hotmail, for example, doesn’t save reputation data for any host sending less than 100 emails to them per day, resulting in an instant ban if they suspect an email is spam.

At the other end of the spectrum, if we run a single outgoing email server and a user sends spam or has their account compromised, we run the risk of mail for all users being blocked.  So, a new solution was needed.

Our new email delivery system

Gradually, over a number of months, we build up the reputation of a range of IP addresses for sending mail.  Once these were prepared, we’ve setup a system using the excellent Postfix mail server.  All outgoing mail from any of our servers (once checked for mail volume limits and spam/virus content) is forwarded to this new service for delivery.

Mail delivery is attempted from the primary server, successful for around 95% of mail.  Where it cannot deliver it passes the mail onto a backup server to retry.  This may be due to rate limiting, reputation, filter rules or any other reason at the receiver end.

Finally, if none of our backup servers can deliver the mail, it’s passed onto MailChannels for them to attempt delivery.  They run further checks on the mail to look for signs that it is ‘spammy’ in case we missed something.  Assuming it’s not they they deliver it from their global network of mail servers.


We automatically add SPF and DKIM records to your account when it’s setup.  You can manage these further  through your control panel by visiting the ‘Email Deliverability’ section in your control panel. These DNS records verify that your email is legitimately coming from your domain, helping to ensure delivery and to help block anyone who many be impersonating you.

Mail Delivery done right at NetWeaver

Using this powerful combination of servers and third party services, you can be confident that if it’s possible for your mail to be delivered, it will be!  Furthermore, this service is included as standard with all of our web hosting accounts.



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