Help Request: Stopping 'Attack'?

["Chris Gray" <cgray vosource com>]

I am using FC1 as a mail server and use ClamAV to protect against
viruses. Clam has killed around 200 emails in the last hour from a
variety of hosts. Each email contained the Worm.SCO.A virus.

What I need to know is: Is this a DoS or some other kind of concentrated
attack and - if so - how do I combat it?

Thanks in advance...

Chris Gray

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Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.567 / Virus Database: 358 - Release Date: 1/24/2004