What's the GPL? WordPress and PEAR Cache Problems

Ben Ramsey explores some of the issues when you write GPLed code that uses code from the PEAR library.
I had forgotten about the differing licenses used by PEAR and WordPress. They’re unfortunately incompatible and you can’t ship PHP licensed code in a GPL project without an “exception clause” in your GPL license. A change to the license of WordPress would require the agreement of *all* copyright holders of code in the project AFAIK.
Thankfully, I don’t ship PEAR Cache with WordPress MU. I use it if it’s installed already, WPMU isn’t dependant on PEAR Cache being available to work.
I think that gets around the incompatibility. Doesn’t it?

Postgrey – Postfix Greylisting Policy Server

Greylisting is an anti-spam and virus measure you can use on your mail servers. When a remote server connects for the first time it’s automatically disconnected and can’t connect for a set time limit (default is 5 minutes). If it’s a real mail server it should keep trying to deliver the mail but viruses and spam will more than likely be stopped cold.

Postgrey is a greylisting server for Postfix that Colm Buckley installed on the machine that runs linux.ie
On Debian, it’s as easy as apt-get install postgrey but then you have to configure Postfix to use it:
Edit /etc/postfix/main.cf and modify the line that starts with:
smtpd_client_restrictions = ...
and add inet:127.0.0.1:60000 to the end of it.
Now, you probably want to enable white listing of clients too so edit /etc/default/postgrey and change so it looks like this:
POSTGREY_OPTS="--inet=127.0.0.1:60000 --delay=300 --auto-whitelist-clients"
You might want to add the IP range for your local network to /etc/postgrey/whitelist_clients so they’re not greylisted:
/^192\.168\.1\..*/ does the job for my situation I think.
Now, restart Postfix and Postgrey and you should see the following message appear in /var/log/mail.info:
Client host rejected: Greylisted for 300 seconds (see http://isg.ee.ethz.ch/tools/postgrey/help)
If you don’t, it’s not working!
Much later… It’s been active for about 20 hours now and I’ve only received about 10 spams, down from well over 200 usually! The delay in delivery is annoying, but it’s something we can hopefully live with!