Lindsay Haisley writes:
On Fri, 2007-08-24 at 17:58 -0400, Sam Varshavchik wrote:
I'd also like to have the option to drop SMTP connections outside of the
LAN for which the IP address of the connecting host has no PTR record
and won't reverse resolve to a name. Is there any way to do this in
Courier?
No, not directly. The only thing you can do is to take the qmail approach,
and have couriertcpd invoke your wrapper, that checks TCPREMOTEIP and
TCPREMOTEHOST, and the invokes courieresmtpd itself.
In Gentoo's build of courier, the stock invocation of courieresmtpd
looks like this.
/usr/sbin/couriertcpd [logger, pid and other options] [block options]
-access=/etc/courier/smtpaccess.dat -address=0 465 /usr/bin/couriertls
-server -tcpd /usr/sbin/courieresmtpd
Do I need to insert a wrapper of some sort in here? Are there any
instructions, examples or prototypes available?
There are no specific examples, but it works just like similar qmail-based
setups. After parsing couriertcpd's options, the remaining arguments form
the command courietcpd runs after establishing a connection, specifically:
"/usr/bin/couriertls -server -tcpd /usr/sbin/courieresmtpd". When couriertls
starts, after parsing its options the remaining argument forms the command
couriertls runs, specifically "/usr/sbin/courieresmtpd".
You would want to replace the last argument with your own wrapper:
/usr/local/sbin/esmtpdwrapper, an executable shell script, that might do
something like this:
#! /bin/sh
if test "$TCPREMOTEHOST" = ""
then
exit 0
fi
exec /usr/sbin/courieresmtpd
So, connections without a hostname in TCPREMOTEHOST get dropped right away,
everyone else runs courieresmtpd, as usual. Read "ENVIRONMENT VARIABLES" in
couriertcpd's man page for a list of environment variables you can use. Your
wrapper inherits the environment all the way from couriertcpd. You said you
don't want to require valid reverse DNS from some IP address ranges, so
you'll need to tweak this logic.
5 messages in net.sourceforge.lists.courier-usersRe: [courier-users] timeouts and ptr ...
