Translations:Complete Virtual Mail Server/SMTP Authentication/35/en

Optionally  can be disabled again. It is very handy for tracking down mailing issues from users. It can however be potentially a security issue, as mentioned above, the users login name is written in the header. On the other hand, if the login name is the local_part of the e-mail address or even the e-mail address then the login name is already known anyway so no big harm there, right? Some caution is advised, but it shouldn't be a huge issue.