Thanks for the input. With my sendmail setup , both relaying and listening on the network device other than the loopback were disabled by default. I had to specifically enable those services. That's what the documentation told me anyway. There were no DNS issues involved at all ; a traceroute to "mail.somedomain.com" showed me that the MX record on our DNS servers were pointing to the right IP address. That's where the sendmail.mc and /etc/access* files became necessary for me.
As for the questions that I "think" I am asking , I realize that I am probably not good enough to ask questions in the format required by super-intelligent Linux list subscribers. What a pleasure life would be if we could rid the world of neuron-depleted and academically challenged bio-entities like myself , who didn't qualify for a MENSA membership. The very best I can do is to try to 'visualize' how all the pieces of this Linux puzzle fit together , ask my questions as best I can , and hope that I don't get too much of a heated response. ----- Original Message ----- From: "David Freeman" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, January 17, 2003 2:41 PM Subject: RE: sendmail configuration on redhat > > > For my own clarification , is there a difference between > > Handling POP3 and SMTP requests , and actually BEING a POP3 / SMTP > server ? > > I guess that depends on what question you think you're asking. > > SMTP = simple mail transfer protocol (from memory, it's a while since I > actually checked that - could be simple mail transport protocol). > > An SMTP server runs on port 25 and handles sending of email as well as > receiving email from clients to be delivered (either locally or to some > SMTP server on the net somewhere). > > POP3 = post office protocol > > A POP3 server runs on port 110 and handles incoming requests for mail > delivery from a client program. > > As both protocols work on different ports they quite happily co-exist on > a single machine. It's no different to running a web server and DNS > server on the same computer. The only thing you can't really do is run > two daemons that want to use the same port and IP address combination. > > That said, on Redhat systems, the SMTP daemon is usually sendmail. This > is NOT a POP3 server. You will also find a POP3 daemon - the newer > releases are incorporated into the IMAP rpm from memory. > > As for the question, if you're "handling" POP3/SMTP requests then you're > most likely operating POP3/SMTP daemons. You could, however, be > proxying such requests which could be said to be "handling" without > being a "server" depending on your definition of those terms. > > Every RH release I've used (seriously from about RH5, earlier as a hobby > thing and I don't really recall for those earlier releases) is readily > capable of acting as a mail server (both POP3 and SMTP) with no real > requirement for altering sendmail.cf although before relaying and the > like became common it used to be necessary to generate your own > sendmail.cf if you wanted that sort of functionality. Most recent > releases have had this capability ready to run. > > Perhaps if the person having problems cannot get mail serving working it > could be related to DNS and, particularly, MX records rather than > configuration of the daemons themselves. > > > If sendmail is > > not > > a POP server , how does it handle the incoming mail ? > > Incoming mail is the job of a mail transport agent, or MTA (a program > that moves mail between servers). The usual protocol is SMTP and this > is what sendmail does. > > Delivery of mail to a client (Outlook Express et al) is the job of a > mail delivery agent, or MDA (a program that waits for client connections > and sends locally stored email to that client). The usual protocol is > POP3, although IMAP is also now popular, and this job is handled by a > POP3 daemon (these days part of the IMAP rpm). > > CYA, Dave > > > > > > _______________________________________________ > Seawolf-list mailing list > [EMAIL PROTECTED] > https://listman.redhat.com/mailman/listinfo/seawolf-list _______________________________________________ Seawolf-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/seawolf-list
