Protecting email servers

Is your email server an undercover spam email sender?

Mail servers that are not correctly configured and secured may be used as relays to send spam email.

What is a relay?

A relay is a email server that allows other computers to send email from it. There are legitimate uses for relaying, i.e. a company with computers spread over several locations may connect to a single email server for all their mail, (this is actually preferred, as it means there is only one system to secure).

So what’s the problem?

When an email server is not properly secured, it may allow unauthorized access to it’s facilities. This means that it can be used remotely to send junk or spam emails. By acting as a relay, the insecure server system gets the blame for the email rather than the original sender.

Once an open mail relay has been identified, a spammer will use it to send huge volumes of mail through the server. A lot of spam originates with organized crime gangs - not people you want to be associated with.

Surely, it won't happen to me!

Think again! There are programs constantly searching the web for open relays.

If your email server is not secure - it will be used by spammers and this also means:

  • Your server may be blacklisted and legitimate email you send will then be rejected by servers using the blacklist you are listed on for spam filtering.
  • Your server may become slow and unstable due to the high volume of email it needs to process.
  • Your bandwidth will be used up by emails.
  • Your server will also receive a massive amount of bounced email as a large proportion of the spam email will be to invalid addresses.

Network Abuse Clearinghouse provide a free tool that tests your email server.