On Mon, Aug 26, 2002 at 09:30:25AM -0700, Craig Dickson wrote:
| Derrick 'dman' Hudson wrote:
|
| > I think both exim and postfix are
| > quality mail servers, and thus would chose one of them.
|
| One important distinction, however: Postfix's design is much more
| security-conscious than exim's.
Both of them are secure, they just have different approaches to
handling it.
| As I recall from when I used to run exim, exim runs as root all the
| time.
No. exim drops its root privileges as much as it can. It performs
most tasks as the "exim user" (user 'mail' and group 'mail' on
debian), but performs deliveries as the local user the delivery is
for, and performs pipes and other "special" deliveries as the user it
is configured to. It does follow the old-school design of using one
binary, though.
| Postfix, on the other hand, is split into various components, of
| which only the port 25 listener (which doesn't actually handle
| requests once a connection is made) runs as root.
True.
| As I see it, the pros and cons of exim and postfix are pretty evenly
| balanced
Agreed.
| except for the security issue.
See above. Exim is written with security in mind, it just doesn't
split itself into many pieces. Philip has been very careful with the
code and checking values, etc, and I'm not aware of any security
advisories in the past year or so (which is when I started paying
attention).
| Both are easy to set up and are more than adequate for most
| purposes.
Agreed.
| (Though I don't recall the Debian exim package using debconf for
| configuration
Nope. Use $EDITOR :-).
| -- instead, you had to run eximconf yourself, which was less
| convenient. Has this changed?)
The 'eximconf' script is debian-specific. All it does is ask some
basic questions and fill out a template config for you. The result is
either
a) a fully working setup, IFF you're needs are exactly reflected
by one of the 4 templates it creates
or
b) a decent skeletal config you can start with and add to (using
$EDITOR) to get all the functionality your site needs
| So the security question was, for me, the deciding factor. I
| switched from exim to postfix and have seen no reason to switch
| back.
My main reason for using exim instead of postifx is sa-exim (see my
previous message, or google, for a URL). Postfix doesn't have any way
to arbitrarily reject messages at SMTP time before it accepts the
message and places it on the queue. The difference between rejecting
and bouncing messages seems subtle, except for when spammers forge the
sender address and you end up with undeliverable bounces on your
queue.
The other main difference is the configuration philosophy. Postfix is
extremely table driven, whereas exim follows the
Chain-Of-Responsibility pattern.
-D
--
Microsoft is to operating systems & security ....
.... what McDonald's is to gourmet cooking
http://dman.ddts.net/~dman/
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