On Mon, 2004-06-28 at 09:49, Cowles, Steve wrote: > Whether or not sendmail can be configured to block e-mail addressed in this > form, from "just" external users?... I don't know. In postfix, I block > external users from addressing e-mail in this form (at least the MAIL FROM > part, not the header from) by first testing if the e-mail was submitted from > someone in my local network. If so, ACCEPT and deliver it. If the e-mail was > submitted from an external source -and- the from address (mail from) is set > to someone in my domain, then reject. By testing in this precise order, > local users can still send e-mail to other local users, but exteternal ones > cannot. Again, I'm only testing the "MAIL FROM", not the header from. i.e. > > C:\> telnet mail.mydomain.com 25 > > 220 mail.mydomain.com ESMTP Postfix (2.1.1) > helo external.otherdomain.com > 250 mail.mydomain.com > mail from: <scowles@xxxxxxxxxxxx> > 250 Ok > rcpt to: <scowles@xxxxxxxxxxxx> > 554 <scowles@xxxxxxxxxxxx>: Sender address rejected: You are NOT from > mydomain.com > DATA > 554 Error: no valid recipients > quit > 221 Bye > Connection to host lost. > > NOTE: The above test generates a 554 (do not pass go, do not collect $200.00 > so to speak) and does NOT generate a bounce. Nice! Also, this test is done > prior to the Data portion of the e-mail being read. > > But if an e-mail is submitted from a system on my local network... > > C:\> telnet mail.mydomain.com 25 > > 220 mail.mydomain.com ESMTP Postfix (2.1.1) > helo enterprise.mydomain.com > 250 mail.mydomain.com > mail from: <scowles@xxxxxxxxxxxx> > 250 Ok > rcpt to: <scowles@xxxxxxxxxxxx> > 250 Ok <----- From/To accepted > DATA > 354 End data with <CR><LF>.<CR><LF> > From: Steve Cowles <scowles@xxxxxxxxxxxx> > To: Steve Cowles <scowles@xxxxxxxxxxxx> > Subject: This is a test. Please ignore! > <----- Delimiter between message header/body. > This is line one of the e-mail body. Steve, If I might ask, what do you configure in main.cf to achieve what you described above? Travis Fraser
