Most email servers, such as Microsoft’s Hotmail or Google’s Gmail, offer built-in spam email filters. These filters are designed to help users customise their inboxes, choosing which emails they’re happy to receive and which they’d like to send straight to junk. They also allow users to unsubscribe from newsletters, block unwanted senders and report emails with content they suspect may be harmful. Therefore, when it comes to protecting yourself against spam emails, enabling and customising your server’s built-in filter is a good first step to take.

Email filters work by analysing incoming messages and trying to determine whether or not they contain irrelevant or harmful content. There are a number of things that filters look out for, including:

  • Unsecure links
  • A suspicious text to image ratio (e.g. too much text, or too many images)
  • Subject titles which include ‘Fwd’ or ‘Re’ in instances where there haven’t been any previous exchanges between the email addresses
  • Strangely formatted email addresses without a recognised domain (e.g.
  • Randomly capitalised letters

Scanning for these features should theoretically block spam from entering your inbox, however some emails manage to slip through the cracks. Spam emailers are becoming much better at forging emails which bypass such filters, and in some cases it can be difficult to distinguish between real and fake emails. Hackers now change their tactics regularly, making it difficult for filters to track them. For instance, some emails now use hash busting techniques. Hash busting uses the random substitution of characters to change the email’s hash sum slightly, allowing it to confuse previous filters set up to stop similar emails.

Another limitation of customised email filters is that they often require users to make their own generalised rules, such as blocking any emails containing particular words or phrases. While this can be effective in sending spam emails straight to junk, you also run the risk of accidentally sending important emails to junk too. Therefore, despite their advantages, it isn’t recommended that email users rely solely on built-in email filters. If this is your only option, there are some extra precautions you should take:

  • Never reply to spam emails. This will only confirm to the sender that you’re a real person, and they’ll become much more interested in trying to scam you.
  • Never share your financial details with a brand you don’t trust. Be aware that banks will never ask you to update your information via email, so don’t be fooled by messages asking you to do so.
  • If you’re sharing your email address with someone, send it in a form difficult for robots to decode. For instance, you could write ‘at’ instead of @, and ‘dot’ for the full stop symbol.

However, if you’re really serious about email safety it’s important to invest in the best anti-spam filter available. Mailcleaner’s anti-spam software uses specially-designed algorithms to detect junk mail, so you can rest assured that you’re protected from phishing scams and malware. Contact us today to see how we could help you!