Hello, I'm trying to auth with telnet on the smtp service but I can't. E-mail clients work just fine. Creating the base64 auth string:Code: $ perl -MMIME::Base64 -e 'print encode_base64("email@example.com\firstname.lastname@example.org\0mypass");' ZmgvcmlhbmUuxx3JnAtZvbGxleQ== Telneting :Code: $ telnet myserver.com 25 Trying my.ip.ad.dre.s.... Connected to myserver.com Escape character is '^]'. 220 hostname ESMTP ehlo mydomain 250-hostname 250-AUTH=LOGIN CRAM-MD5 PLAIN 250-AUTH LOGIN CRAM-MD5 PLAIN 250-STARTTLS 250-PIPELINING 250 8BITMIME auth plain ZmgvcmlhbmUuxx3JnAtZvbGxleQ== 535 auth failure Server log says:Code: smtp_auth: smtp_auth: FAILED: mypass - no such user from [email]email@example.com[/email] Some facts : * The same login/password works when poping with telnet and with any mail client (pop and smtp) * The server is a 8.1 Plesk installed on Debian Sarge. * The only modification made is the "-Rt0" in /etc/xinetd.d/smtp_psa Note that "mypass" is in the logs where there is usually a login... maybe my auth creation is wrong ? It's weird because the Plesk's knowledge base says to do so. many thanks for some help skrieg.