James Vahn wrote: > I'm unsure why sendmail runs as root if exim/postfix don't.
In order to deliver mail to the local user's mailbox the MDA (mail delivery agent) needs to run as the user. Same for being piped into a mail filter such as spamassassin. In order to switch to a user the program needs root capability. Also to bind to the network port 25 (privileged ports below 1024) requires root. Since sendmail is one single program it is that program that runs as root. In Postfix there is a root run master program for that purpose. But the other tasks are run as a non-root user. > Well, I'm not exactly convinced that anyone should be saying anything > like "dump sendmail, run postfix or exim" (a poor quote, sorry). I have opinions and when asked I won't be shy about sharing them. I think Postfix is definitely a better MTA than Sendmail. I will keep my previous recommendation. > Do they have nice config/setup programs? I don't like sendmail's > very much, it requires manually editing sendmail.conf. Not a > particularly difficult task, but still.. :( > > ~# dpkg-reconfigure sendmail ...Doesn't work. dpkg-reconfigure postfix # works dpkg-reconfigure exim4 # works > The examples I can think of are very few. Using m4 macro's is not > complicated.. Exim is complicated. While the m4 macros cover most common things they don't cover every possible case. Here is an example. Years ago in sendmail I needed to deliver mail in a particular way. I needed machines in the same domain to be delivered directly with smtp but mail outside the domain to be delivered to a smart host. I won't get into the DNS issues with why using MX records was insufficient in my case. Here is the best configuration I found at the time for sendmail. There was no m4 macro support for this. That was a while ago and who knows but there might be now. define(`SMART_HOST',`esmtp:smtp.$m.')dnl LOCAL_NET_CONFIG R$* < @ $* .$m. > $* $#esmtp $@ $2.$m $: $1 < @ $2.$m > $3 With postfix I changed the transport map file to have the first line and the main.cf to have the second line. To me this is much simpler. If the mail matches the left hand side then do the action on the right hand side. .example.com smtp: relayhost = smtp.$mydomain Later I needed specific routing to get around firewalls creating isolated network bubbles. I modified the transport map as follows. subdomain.example.com smtp:smtp.subdomain.example.com .example.com smtp: relayhost = smtp.$mydomain To do the same with Sendmail I believe (without testing) I would have needed this. I think this would work. Perhaps now there is an m4 macro that covers this case. (shrug) define(`SMART_HOST',`esmtp:smtp.$m.')dnl LOCAL_NET_CONFIG R$* < @ $* .$m. > $* $#esmtp $@ $2.$m $: $1 < @ $2.$m > $3 R$* < @ $* .subdomain.$m. > $* $#esmtp $@ $2.subdomain.$m $: $1 < @ $2.$m > $3 The common thing that a zillion other people are doing is usually going to be the streamlined case that is simple. The m4 macros cover those cases well enough. But just the same in the above examples I find the postfix table driven configuration to be quite powerful and yet still intuitive. Bob
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