Testing for and stopping mail relaying

[Chris Wong]

On Tue, 26 Dec 2000, Erich S. wrote:

> In spare time during the holidays, I've wanted to find more
> information on securing sendmail 8.9.3 against relaying was well as
> blocking spammers.

I'm a bit rutsy... standby

In the file called /etc/sendmail.cf examine a line.. it should read
something like:

# Hosts that will permit relaying ($=R)
FR-o /etc/mail/relay-domains

In general, all non-ancient (post 1.2) distributions should have some sort
of anti-relaying feature. I should hope so.

Also, you may wish to check the file /etc/sendmail.cw

Or whatever your Fw macro expands to. My /etc/sendmail.cf has something
like this:

Cwlocalhost
# file containing names of hosts for which we receive email
Fw/etc/sendmail.cw

I then placed a couple of other entries in there. Aliases that my machine
goes by.

> Are there any relatively simple HOW-TO sites that deal with this? The
> information at sendmail.org that I saw seems to be more for experienced
> sendmail admins.

Beats me. 

> Are there other, easier to admin mailservers that can replace
> sendmail? What are the downsides to using them? I've heard some good
> things about qmail, but not sure if there are disadvantages to using
> it vs. sendmail. I'm using sendmail only since it's what is installed
> now, and what appears to be installed on most other boxes I've come in
> contact with.

qmail qmail and qmail.

Qmail is very easy to understnad ONCE you forget everything you know about
sendmail.