[EMAIL PROTECTED] a écrit : >> ------------------------------ >> >> Date: Tue, 02 Dec 2008 14:50:21 +0100 >> From: mouss <[EMAIL PROTECTED]> >> Subject: Re: Problems with backscaters and require authentication >> >> [EMAIL PROTECTED] a écrit : >>> Hi, >>> >>> i have some problems with spammers and i would like to ask how to set >>> postfix to validate sender email addresses only for our domains. Is >>> there some way to do this? >> what do you mean exactly by "validate"? check that the address exists? >> you can use reject_unlisted_sender. >> >>> Other thing that i want to ask. I have this problem: >>> >>> i connect thru telnet to the smtp server and send email this way: >>> >>> helo myhostname.example.com >>> mail from:[EMAIL PROTECTED] >>> rcpt to:[EMAIL PROTECTED] >>> data >>> something here >>> . >>> quit >>> >>> mydomain.com is domain from the system. >>> >>> i'm able to send spam to this user, using the same email address in >>> "mail from" field. >>> >>> Is there some way to protect my mailserver from this kind of things for >>> our domains. If "mail from" use our domains (for example >>> [EMAIL PROTECTED]), then to require authentication. >>> >> >> smtpd_sender_login_maps = >> hash:/etc/postfix/sender_login >> >> smtpd_sender_restrictions = >> reject_sender_login_mismatch >> >> >> http://www.postfix.org/postconf.5.html#smtpd_sender_login_maps >> >> > > Hi, thanks for the reply. Yes i mean to check if sender exists, but only > for our domains, not for all senders, because there are mail servers > that reject this kind of checking. > > I suppose that when i configure this way my system, it will not make > problems with rest of senders, right?
yes, it's ok. use reject_unlisted_sender in smtpd restrictions. you can use (with or without reject_unlisted_sender): smtpd_reject_unlisted_sender = yes
