Strange... Apparently, your message did not reach my mail server...
Anyway... When I did your proposed change, the server did the right thing:
$ ./crash-server.sh adding new entry "cn=bugtestgroup_3301,ou=groups,dc=cefetrs,dc=tche,dc=br" ldap_add: Constraint violation (19) additional info: some attributes not unique
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Humm... Now, I know why... Your mail server does not have a 'PTR record'...
Jul 1 08:59:20 cmi postfix/smtpd[26501]: NOQUEUE: reject: RCPT from unknown[194.244.21.122]: 450 4.7.1 Client host rejected: cannot find your hostname, [194.244.21.122]; from=ando@sys-net.it to=amg1127@cefetrs.tche.br proto=ESMTP helo=<mail2.sys-net.it> Jul 1 10:09:19 cmi postfix/smtpd[30576]: NOQUEUE: reject: RCPT from unknown[194.244.21.122]: 450 4.7.1 Client host rejected: cannot find your hostname, [194.244.21.122]; from=ando@sys-net.it to=amg1127@cefetrs.tche.br proto=ESMTP helo=<mail2.sys-net.it> Jul 1 11:19:22 cmi postfix/smtpd[3467]: NOQUEUE: reject: RCPT from unknown[194.244.21.122]: 450 4.7.1 Client host rejected: cannot find your hostname, [194.244.21.122]; from=ando@sys-net.it to=amg1127@cefetrs.tche.br proto=ESMTP helo=<mail2.sys-net.it> Jul 1 12:29:20 cmi postfix/smtpd[10287]: NOQUEUE: reject: RCPT from unknown[194.244.21.122]: 450 4.7.1 Client host rejected: cannot find your hostname, [194.244.21.122]; from=ando@sys-net.it to=amg1127@cefetrs.tche.br proto=ESMTP helo=<mail2.sys-net.it>
# host 194.244.21.122 Host 122.21.244.194.in-addr.arpa not found: 3(NXDOMAIN)