terom@mail:/etc/postfix$ cat /etc/postfix/ldap-forward.cf
version = 3

# lookup by username, and redeliver to external address if set
search_base = ou=People,dc=paivola,dc=fi
query_filter = (uid=%s)
result_attribute = mailRoutingAddress

terom@shell ~ $ ldapmodify -x -D uid=terom,ou=People,dc=paivola,dc=fi -W
# Enter LDAP Password:
dn: uid=terom,ou=People,dc=paivola,dc=fi
changetype: modify
replace: mailRoutingAddress
mailRoutingAddress: terom@fixme.fi
# modifying entry "uid=terom,ou=People,dc=paivola,dc=fi"

terom@mail:/etc/postfix$ /usr/sbin/postmap -q terom ldap:/etc/postfix/ldap-forward.cf
terom@fixme.fi

zapotek:/etc/exim4 :: mail terom@paivola.fi
Subject: test 2
test
Cc:

terom@mail:/etc/postfix$ sudo tail -n500 /var/log/mail.log | grep terom
Mar 25 21:34:15 mail postfix/cleanup[13614]: 7C94ECA3EC: hold: header Received: from zapotek.paivola.fi (zapotek.paivola.fi [194.197.235.230])??(using TLSv1 with cipher AES256-SHA (256/256 bits))??(No client certificate requested)??by mail.paivola.fi (Postfix) with ESMT from zapotek.paivola.fi[194.197.235.230]; from=<terom@zapotek.paivola.fi> to=<terom@paivola.fi> proto=ESMTP helo=<zapotek.paivola.fi>
Mar 25 21:34:19 mail postfix/qmgr[13594]: 562E61804E: from=<terom@zapotek.paivola.fi>, size=661, nrcpt=1 (queue active)
Mar 25 21:34:19 mail postfix/qmgr[13594]: ACB221804F: from=<terom@zapotek.paivola.fi>, size=1141, nrcpt=1 (queue active)
Mar 25 21:34:19 mail postfix/local[13605]: 562E61804E: to=<terom@paivola.fi>, relay=local, delay=4.5, delays=4.1/0/0/0.35, dsn=2.0.0, status=sent (forwarded as ACB221804F)
Mar 25 21:34:20 mail postfix/smtp[13628]: ACB221804F: to=<terom@fixme.fi>, orig_to=<terom@paivola.fi>, relay=zerg.fixme.fi[84.20.150.21]:25, delay=0.38, delays=0.26/0/0.07/0.05, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as F070894304)