OT - Exchange Server missuse

[Phillip Grobler <pfg@xxxxxxxxxxxxx>]

Hi

Could someone perhaps assit me . We are a small small company using
Exchange server 5.5 for our e-mail it seems as if someone is missusing
our mail server
to send spam. The seders domain is desertmail.com.
DO yoiu have any advice on how to stop him.

I had a look at increasing the security but don't quite now where to
start
any help would be apprtiated

Phillip Grobler


begin:vcard 
n:Grobler;Phillip
tel;cell:+27 82 787 9502
tel;fax:+27 21 9301829
tel;home:+27 21 9304469
tel;work:+27 21 9304469
x-mozilla-html:FALSE
url:www.grobler.co.za/cats/
org:C.a.T.S.
adr:;;P.O. Box 2238;Bellville;Western Cape;7535;South Africa
version:2.1
email;internet:pfg@xxxxxxxxxxxxx
fn:Phillip
end:vcard