SMTP Auth does not work (535 Error: authentication failed)

Hi.
Our SMTP server requires SMTP authentication and this works well in Outlook
Express.
However in a Telnet Session (and in my own software code as well), I always
receive
535 Error: authentication failed

Which are the right questions, that I should ask my external email provider
in order to identify and solve the problem??????


Thanks in advance
Friedhelm

My session looks like
220 p15122007.pureserver.info ESMTP Postfix
ehlo budnick
250-p15122007.pureserver.info
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-STARTTLS
250-AUTH PLAIN LOGIN DIGEST-MD5 CRAM-MD5
250-AUTH=PLAIN LOGIN DIGEST-MD5 CRAM-MD5
250-XVERP
250 8BITMIME
auth plain <VeryCarefullyEnteredMimeDecodedStringLikeUser\0Us er\0Pass>
535 Error: authentication failed
auth login
334 VXNlcm5hbWU6
<VeryCarefullyEnteredMimeDecodedUserName>
334 UGFzc3dvcmQ6
<VeryCarefullyEnteredMimeDecodedPassword>
535 Error: authentication failed

Friedhelm Budnick wrote:

> Hi.
> Our SMTP server requires SMTP authentication and this works well in
> Outlook Express.
> However in a Telnet Session (and in my own software code as well), I
> always receive
> 535 Error: authentication failed
>
> Which are the right questions, that I should ask my external email
> provider in order to identify and solve the problem??????
>
What do you mean? Is this your own postfix server or
do you have this problem on your own box?

Normaly, you can set -v at the end of smpt string in /etc/postfix/master.cf
smtp inet n - n - - smtpd -v
and whatch /var/log/mail

The other thing is: Did you decode your string in base64 ?
Normaly you can make it with perl:
perl -MMIME::base64 -e "print decode_base64('user\0user\passwd\0');"

regards
Markus