Sendmail

[jc at trillian.mit.edu (John Chambers)]

Jerry Callen wrote:
	John Abreau wrote:
	> On Tue, 20 Apr 1999, Jerry A Clabaugh wrote:
	> > I've been able to RTFM for most unix packages, but Sendmail has me
	> > stymied. Just for starters, how do you find out what version of
	> > Sendmail you're running?  My box at work has Sendmail which was
	> > installed when I installed SuSE Linux, so I don't know a priori.
	> 
	> Telnet to port 25 of your machine, and the ESMTP line it spits out
	> includes the version number.

	Now *THIS* is beautiful piece of email. It demonstrates:

	- the usefulness of mailing lists like this one, and

That it is ...

	- a truly classic item to be added to the Unix Hater's list of
	  strange and unwonderful arcana. 

... but I wouldn't agree with this at all. First, it's hardly arcane.
Telnet  is  one of the most widespread programs in the industry; even
Microsoft supplies it.  It implements a  standard  protocol  that  is
documented  in  the  best-known  set  of  standards  that  exist, the
Internet RFCs.  And the SMTP (Simple Mail Transfer Protocol)  server
that lives on port 25 is also one of the Internet's oldest standards.
Both the telnet and  SMTP  protocols  are  among  the  simplest  comm
protocols  ever  invented.   SMTP is easily typed by a human; I do it
routinely to test network connectivity.

Also, strictly speaking, none of this has anything at all to do  with
Unix. Telnet and SMTP are Internet standards, not Unix internals, and
they are implemented the same on non-Unix machines.  If your  machine
is running an Internet "SMTP" server, I can telnet to it and send you
email by hand, without knowing or caring what OS you are running.  It
even  works with Microsoft systems, believe it or not.  And even more
surprising, it also works with many IBM mainframes.

You can also do something very similar with web servers.   Try  this,
for some machine foo.bar.com that you suspect has a web server:
   $ telnet foo.bar.com 80
   GET / HTTP/1.0

Then hit the Return key twice.  You'll get back a set of HTTP  header
lines  that  identify  the  server,  a blank line, and their root web
page.  Instead of just the /, try typing a file path and  watch  what
happens.   Again,  this  has nothing to do with Unix (except that the
first web servers ran on Unix systems). It will work with web servers
running on any machine, because it's merely using the HTTP protocol.

You may hate Unix, and you may hate the  fact  that  these  protocols
make  suth  things so easy, but if you blame Unix for the latter, you
are placing your blame entirely on  the  wrong  parties.   Blame  the
Internet gang instead.

(Oh, and blame Bill Joy for sendmail. And for csh and vi. ;-)



--
Modern GUIs are very well designed, for people with three hands. The
real problem has been how slow customers have been to make necessary
hardware upgrades to meet the requirements of the software.
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