General information about email viruses, spam and security.

There are many myths and misunderstandings about email security, viruses and spam. But one thing is certain: virus and spam emails are a great nuisance and cost businesses a lot of money every day.

Security and the “sender address”

The sender address is basically (very simplified, of course) the main problem with today’s email standards, because nothing stops you from writing a sender address on your emails that you have no access to at all. Viruses and spam exploit this to make an email seem more trustworthy to unsuspecting users. In other words, you can’t trust at all who has sent you a given email.

If your emails are delayed

As part of the protection, we use something called “greylisting”. This means that the first time a sender meets our servers, it is told to try again in a little while. Every mail server sending genuine email will try again a little later. Many spammers, on the other hand, give up straight away. This can cause a delay of typically up to 10 minutes the first time you receive email from a sender you haven’t had mail from before, or haven’t had mail from for a long time. In return, this alone spares you a lot of spam.

Scanning for viruses and spam

All mail passing through our servers is scanned for both viruses and spam (unwanted advertising mail), and the user is informed if a mail tests positive for either.

Both measures aim to make reading email a little less dangerous, but the procedure differs depending on whether it’s a virus or spam:

Viruses:

If an email is found to be infected with a virus, it is deleted immediately, and both the sender and the intended recipient are informed. Please note that in this context a number of file types are not allowed as attachments, simply because these file types have traditionally been used a great deal to carry viruses. Emails with attachments of the following types are deleted just like virus-infected mail:

.SCR

.PIF

.VBS

.SHS

.EXE

.COM

.BAT

.HTA

.CPL

If you compress the files with, for example, ZIP before sending, they won’t be affected by this filter.

Spam:

All mail undergoes up to 10 different analyses in an attempt to establish whether it is spam or not, but unlike viruses, spam can’t be identified quite so clearly, so there will always be errors, either as spam that slips through the system untouched or as “innocent” mail that is treated as spam.

That’s why spam isn’t deleted, but marked with “SPAM:” in the subject – it’s then up to each user to decide whether this mail should be deleted automatically, moved to a special folder or deleted manually.

A free and easy tool for mail problems is: http://mxtoolbox.com/, where you can check your own status as an email sender, e.g. whether your domain is blacklisted.