On 06/06/2011 10:14 AM, Raj Mathur (राज माथुर) wrote: > On Monday 06 Jun 2011, Rony wrote: >> [snip] >> However, why is the ISP allowing this >> unknown user which postfix is relaying when I have everything set in >> the smtp_auth_ part of postfix? Suppose there is a flaw in my >> settings, shouldn't the ISP's mail server reject those mails when >> the username and password do not match with their list? That user >> has been deleted from their server. > Because the ISP is relaying based on the authentication your server > provides (which could be IP or login based),
I don't have any IP based auth. only username and password. The ex-user's name and password are deleted so which credentials are used for auth.? What I found from the docs is that if the sender client is in the 'mynetworks' parameter, they can send without authentication unless the smtpd_auth is enabled and user names and passwords are set using saslauthd or sasld. For relay to the remote server, postfix only needs smtp_auth and a text based list of users/passwords which I use. What puzzles me is that even if postfix relays the message to the ISP smtp, shouldn't the security of the ISP reject the message as that user does not exist? Tomorrow, anyone will set up an smtp server using postfix without knowing any passwords and send mails as a fake user via the ISP's smtp. > and not on the auth the > original client provided to your server. In other words, once the mail > gets into your server, it will get relayed regardless of who sent it. > -- Freedom is a shared resource. Take some, leave the rest for others. Please trim your replies. Avoid cross posting to other lists. Post your replies below the relevant original text, leaving a line space. Regards, Rony. -- http://mm.glug-bom.org/mailman/listinfo/linuxers
