CentOS5+Postfix2.3.3+cyrus-sasl2.1.22(付属のrpm)でSMTP-AUTHの設定を一通り行い、telnetで動作テストすると、 $ telnet localhost 25 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. 220 www.doyouphp.jp ESMTP Postfix ehlo doyouphp.jp 250-www.doyouphp.jp 250-PIPELINING 250-SIZE 10240000 250-VRFY 250-ETRN 250-AUTH PLAIN LOGIN 250-ENHANCEDSTATUSCODES 250-8BITMIME 250 DSN quit 221 2.0.0 Bye Connection closed b