[Sunhelp] ?: how to avoid sending the spam-mail on the sendmail

[Wonkyu Chang - Sun Korea SE]

Dear experts,

Could you tell me how to read the below /var/log/syslog?
Can I pick up the client who issued the spam-mail from the mail logging as like 
the below?

Apr  2 03:32:27 provin sendmail[13247]: DAA13247: from=<return at infomail.co.kr>,
size=28136, class=0, pri=58136, nrcpts=1, msgid=<200004011832.DAA13247 at provin.pr
ovin.kyongnam.kr>, bodytype=8BITMIME, proto=SMTP, relay=[211.40.176.143]   


Apr  2 07:40:25 provin sendmail[14020]: HAA14020: from=<leehyo at ppp.kornet21.net>
, size=1289, class=0, pri=31289, nrcpts=1, msgid=<12E108EC.812AA29B at ppp.kornet21
.net>, bodytype=8BITMIME, proto=ESMTP, relay=[168.126.3.42]


Please, give me some guidance on avoiding the spam-mail.

Thanks,
WK Chang