Urgent, being used as spam relay Please Help!

a simple configuration:

edit a file /etc/sendmail.relaylist with your own domain and other
domain that you want to permit relaying.

put in your mc file (if you use the m4 kit configurator) or directly in
/etc/sendmail.cf (but you need to remove the two lines LOCAL_*) the
configuration below.

Restart your sendmail.

You need to use the latest version of sendmail (8.8.8) => there's no
known security hole.

The last point, take care with TAB in the mc file or with
/etc/senmail.cf file (look at the comments ;-) )

----8<--------- Cut here --------------------------

LOCAL_CONFIG
FR-o /etc/sendmail.relaylist

LOCAL_RULESETS
# TAB stop should be -><- here
Scheck_rcpt
# anything terminating locally is ok
R< $+ @ $=w >           $@ OK
R< $+ @ $* $=R >        $@ OK

# anything originating locally is ok
R$*                     $: $(dequote "" $&{client_name} $)
R$=w                    $@ OK
R$* $=R                 $@ OK
R$@                     $@ OK

# anything else is bogus
R$*                     $#error $: "571 Relaying Denied"

----8<--------- Cut here --------------------------

A+

PS: sorry for my english ;-)
-- 
SeB-]