Exchange SMTP Mail Looping Problem.

We are using exchange 2000 server with sp3 for internal mail use.the
incoming internet mails are via sun solaris its forwarding to exchange
2000 server. the outgoing Internet mails are forwarding from exchange
to sun solaris.fine.Now some mails are delivering multiple times to
user mailbox.So i checked the Logs of both server. In the exchange
server log i found that the message are stored multiple times in the
user store box.
So please help to identify this problem..
the Exchange server Log is
——— —————–
SMTP : Message submitted to Advanced Wueuing
SMTP : Started Message Submission to Advanced queue
SMTP : Message submitted to Categorizer
SMTP : Message delivered Locally to (User E-mail address)
SMTP store Driver : Message delivered Locally to store to (User E-mail
address)
SMTP : Message submitted to Advanced Wueuing
SMTP : Started Message Submission to Advanced queue
SMTP : Message submitted to Categorizer
SMTP : Message delivered Locally to (User E-mail address)
SMTP store Driver : Message delivered Locally to store to (User E-mail
address)
SMTP : Message submitted to Advanced Wueuing
SMTP : Started Message Submission to Advanced queue
SMTP : Message submitted to Categorizer
SMTP : Message delivered Locally to (User E-mail address)
SMTP store Driver : Message delivered Locally to store to (User E-mail
address)
……………
The Sun solaris Log is
————————
Feb 20 10:35:03 gatekeeper sendmail[29591]: [ID 801593 mail.info] j1K6Z2R29591: from=, size=6279, class=0, nrcpts=1,
msgid=, proto=ESMTP, daemon=Daemon0, relay=localhost [127.0.0.1]
Feb 20 10:35:03 gatekeeper sendmail[29589]: [ID 801593 mail.info] j1K6Z1C29587: to=, delay=00:00:01, xdelay=00:00:01, ma
iler=esmtpvw, pri=126059, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (j1K6Z2R29591 Message accepted for delivery)
Feb 20 11:35:03 gatekeeper sendmail[29592]: [ID 801593 mail.notice] j1K6Z2R29591: timeout waiting for input from mx2.company.com. during client
DATA status
Feb 20 11:35:03 gatekeeper sendmail[29592]: [ID 801593 mail.info] j1K6Z2R29591: to=RECEIPENT ADDRESS, delay=01:00:01, xdelay=01:00:00,
mailer=esmtp, pri=34530, relay=mx2.Company.com. [10.50.200.2], dsn=4.0.0, stat=Deferred: Connection reset by mx2.company.com.