On 03/23/13 15:12, Evan Root wrote: > Gilles, > > How would you recommend a new unix admin learn OpenSMTPD? > > -Evan >
Same way you learn most things in this business... sit down and "do it". In my case, I just recently had my local Internet provider start blocking outbound port 25 traffic, so all my internal machines couldn't get to my external mail server to send out their daily reports. There are a several of potential solutions to this...last time they did that, I did a little PF redirection magic on both my home firewall and my mail server. This time, though, I figured I'd set up an internal mail server and a little DNS magic to snag all the queued up mail (rather than reconfiguring 20 machine), and this would be a good time to learn OpenSMTPD (I know...lame of me to not have been doing anything with it before. Life has been..busy) (and yes, my personal designs are way more complicated than they should be...it gets it out of my system so I'm more inclined to go with really simple solutions for my employer... also, while simple systems have simple problems, complex systems and their complex problems are good training, if bad engineering) I already had an internal IMAP server, so figured that would be the logical place to put the SMTP server for daily reports. Started with the sample config file...and had things running rather quickly. Spent a little time testing it using telnet (hint: opensmtpd is picky -- you have to put < > around e-mail addresses, which is "correct", and all real mail servers do it, but many internet guides to talking SMTP via telnet skip over that little detail, and many major mail servers will happily let you not put them in) (and yes, I do consider my ability to remember the details of an smtp session a measure of quality of life...if I don't have to look it up, my life sucks. It's been a couple years since I managed mail servers for a living, and I've managed to forget if it is "rcpt to" or "rcpt from" or whatever, so life is good). While reading the man pages I discovered, joy of joys, OpenSMTPd can drop mail directly into a maildir! So, just injected my log traffic directly into the already existing maildirs. Life is so good. So, I did my dns hocus-pocus, and a few minutes later, hundreds of backlogged messages and error messages, and error messages from the error messages were rolling into my inbox. OpenSMTPd's config file format just rocks. You really don't need a 500 page book to tell you how to use OpenSMTPd. Just read the man pages -- man 8 smtpd, man 5 smtpd.conf and look at the sample provided. You DO need to understand Internet E-mail...and there, the "Bat Book" is still a good guide, you can just skip the parts about configuring sendmail (that's most of the book). There aren't five million options to OpenSMTPD. That being said... There are two Internet services that you really should almost need a license to be allowed to run -- DNS and e-mail, as if you do it wrong, you can mess up OTHER people, not just yourself. If you think running e-mail is fun, you are probably doing it wrong. If you are good at it, you probably hate doing it. Wonderful as OpenSMTPD is, it probably only simplifies about 5% of the total of running a mail server...but that's still a nice feature. (if you don't understand what I mean...I'm responding to an e-mail that was originally sent Mar 23, and arrived in my inbox on April 1. Now, imagine the customer calling you up to find out why...and look at the headers and see that more than one thing seems to have gone wrong...and there are twenty other people on hold right now, each with different problems) Nick.
