Virus Scanning

Our servers are now scanning incoming and outgoing mail for viruses. That's free anti-virus protection for your mail! Our online antivirus system will:

• Block thousands of known viruses (such as BugBear, Klez etc)
• Block virus-like attachments

Attachments which end in any of the following are dropped:

adp,bat,com,cpl,lnk,pif,reg,scr,shs,wsc,wsf,wsh

Those are the ones which are both dangerous and unlikely to be sent for any valid reason.

Attachments which end in any of the following are NOT being dropped but a warning message will appear in the main message advising the recipient that opening the attachment could be dangerous:

exe,cmd,jse,sct,shb,url

The reason these are not being dropped is that we believe it is likely that the files would be sent for valid reasons.

Regardless of the above rules, an attachment may be dropped if it appears to be dishonestly reporting itself. For example, a .exe file with a content-type of .wav, .jpg, etc would be dropped automatically. These need to be dropped because they can infect a machine without the person explicitly choosing to open them. Also, it is extremely unlikely that this sort of filename/content-type combination would be used for a valid reason.

Finally, while the overwhelming majority of messages passing through our servers are scanned thoroughly for viruses, please note that the following limits apply:

• Messages larger than 2 MB are not scanned - scanning very large attachments is extremely resource intensive so is not appropriate in a shared hosting environment. Please note however, that the vast majority of viruses are spread in files smaller than 2 MB.
• If a message contains 4 or more binary attachments, then only the first three are scanned. Again, this is a necessary limit to prevent overuse of resources, and we anticipate that it will affect very few messages.

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