"Strange" maillog entries - am I being used as a relay?

[Mike Pelley]

Folks - I noticed some strange errors in my logwatch report and when I checked my maillog I found the entries below.  I have SMTPS with TLS set up for authentication.  Does this mean I'm being used as a relay?

maillog:Mar 29 09:30:24 zeus postfix/smtpd[26863]: connect from unknown[216.113.195.131]
maillog:Mar 29 09:30:24 zeus postfix/smtpd[26863]: setting up TLS connection from unknown[216.113.195.131]
maillog:Mar 29 09:30:24 zeus postfix/smtpd[26863]: TLS connection established from unknown[216.113.195.131]: TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)
maillog:Mar 29 09:30:25 zeus postfix/smtpd[26863]: 0A1267031D: client=unknown[216.113.195.131]
maillog:Mar 29 09:30:25 zeus postfix/smtpd[26863]: 0A1267031D: reject: RCPT from unknown[216.113.195.131]: 450 <wjwwwdk at pelleys.com>: User unknown in local recipient table; from=<> to=<wjwwwdk at pelleys.com> proto=ESMTP helo=<email.noproblemnetworks.com>
maillog:Mar 29 09:30:27 zeus postfix/smtpd[26863]: disconnect from unknown[216.113.195.131]

Thanks,
Mike