maillog :

postfix/smtpd[9731]: connect from smtpclu-6.eunet.yu[194.247.192.231]
postfix/smtpd[9731]: warning: disct_ldap_lookup: Search error -5: Timed out
postfix/smtpd[9731]: NOQUEUE: reject: RCPT from smtpclu-6.eunet.yu[194.247.192.231]: 451 <olja.m@topolauniverzal.com>: Temporary lookup failure; from=<cba@EUnet.yu> to=<olja.m@topolauniverzal.com> proto=ESMTP helo=<smtpclu-6.eunet.yu>