On Sun, 2004-05-16 at 05:40, Cowles, Steve wrote: > Ow Mun Heng wrote: > > Is this correct behaviour? I thought that to send emails you need to > > either be authenticated (SMTP auth) or be on the same IPs as your > > ISP?? > > > > Or is this what's happening? Sendmail is actually querying DNS root > > servers and then upon getting the MX server, it connects straight to > > port 25 of that MX Server and sends it? If that's the case, what's > > stopping it from being a relay??? > > > > /curious > > By default, redhat configures sendmail (actually sendmail.mc) to only accept > smtp requests from localhost. You would have to override that setting to > have sendmail accept smtp requests from other hosts on your LAN. The maillog > entry prior to the one you posted should show where the e-mail in question > was submitted from. Based on your post where you stated you have NOT > modified sendmail.mc, I'd be willing to bet it was submitted from localhost. > Take a look! > > As for your concern about being an open-relay... even if you were to modify > sendmail.mc and allow sendmail to accept smtp connections from another host Nope. I'm not concerned about being an open relay. I know i"m not. I'm just curious on how mails gets sent to the recipients. Alexander posted a longish answer to that. Still digesting it, but I think I sort of understand how things flow.
