Высылаю фрагмент логов (smtpd -v):
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 220 mail.server.ru Postfix Ubuntu 7.10 (Server)
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: < unknown[192.168.34.87]: EHLO [127.0.0.1]
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 250-mail.elma-electro.ru
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 250-PIPELINING
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 250-SIZE 10240000
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 250-VRFY
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 250-ETRN
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 250-STARTTLS
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 250-AUTH LOGIN PLAIN
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: match_list_match: unknown: no match
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: match_list_match: 192.168.34.87: no match
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 250-AUTH=LOGIN PLAIN
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 250-ENHANCEDSTATUSCODES
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 250-8BITMIME
Jan 25 00:45:27 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 250 DSN
Jan 25 00:45:39 Server02 postfix/smtpd[30989]: < unknown[192.168.34.87]: AUTH PLAIN AHRlc3QAdGVzdDgw
Jan 25 00:45:39 Server02 postfix/smtpd[30989]: xsasl_cyrus_server_first: sasl_method PLAIN, init_response AHRlc3QAdGVzdDgw
Jan 25 00:45:39 Server02 postfix/smtpd[30989]: xsasl_cyrus_server_first: decoded initial response
Jan 25 00:45:39 Server02 postfix/smtpd[30989]: warning: unknown[192.168.34.87]: SASL PLAIN authentication failed: overflowed buffer
Jan 25 00:45:39 Server02 postfix/smtpd[30989]: > unknown[192.168.34.87]: 535 5.7.0 Error: authentication failed: overflowed buffer