[cobalt-users] Maillog entries

["Jeff S. Lucido" <JSLucido@xxxxxxxxxxx>]

I have noticed a few entries in my maillog file over the past three days 
that is bothering me. Here is the entry (which appears almost every two 
minutes, 24 hours a day):

Mar  8 10:58:14 senna sendmail[26237]: KAA26237: ruleset=check_mail, 
arg1=<Poetry.com@xxxxxxxxxxxxxxxxxxxxxx>, relay=artsandkids.com 
[38.203.66.36] (may be forged), reject=451 
<Poetry.com@xxxxxxxxxxxxxxxxxxxxxx>... Sender domain must resolve

Mar  8 10:58:14 senna sendmail[26237]: KAA26237: 
from=<Poetry.com@xxxxxxxxxxxxxxxxxxxxxx>, size=0, class=0, pri=0, nrcpts=0, 
proto=E SMTP, relay=artsandkids.com [38.203.66.36] (may be forged)

Mar  8 10:59:35 senna sendmail[26278]: KAA26278: ruleset=check_mail, 
arg1=<Poetry.com@xxxxxxxxxxxxxxxxxxxxxx>, relay=artsandkids.com 
[38.203.66.36] (may be forged), reject=451 
<Poetry.com@xxxxxxxxxxxxxxxxxxxxxx>... Sender domain must resolve

Mar  8 10:59:35 senna sendmail[26278]: KAA26278: 
from=<Poetry.com@xxxxxxxxxxxxxxxxxxxxxx>, size=0, class=0, pri=0, nrcpts=0, 
proto=E SMTP, relay=artsandkids.com [38.203.66.36] (may be forged)

From what I can tell (I wouldn't even consider myself a novice) it looks 
like someone from this domain is trying to send mail through my server. I 
do not host this domain (watermark.com) and I only have relaying turned on 
for a few select domains, none of which are listed above.

Any help or advice would be greatly appreciated.

Thanks in advance,
-JSLucido