Monthly Archives: February 2005

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!

Where's me culture? It's in Cork!

Cork City is the European Capital of Culture 2005 and despite a small budget available to the organisers they’re putting on a bit of a show this year!
Not everyone agrees with their program of activities and so the Where’s Me Culture? movement quickly became an “alternative” to the official festivities. As they put it themselves:

We believe that responsibility for celebrating Cork as a cultural city is neither the sole preserve nor the sole responsibility of the Cork 2005 office. Cultural expression is the responsibility of all.
We believe that imagination and energy and a willingness to help each other is more important than a large budget.
We believe in the cultural importance of having fun.

A walk has been organised for this weekend, and more details are available on their site. I won’t be there, but enjoy it, the Line is a lovely walk and should be fun!
If you have photographs of Cork, you might be interested in Cork Space.com. It’s a project that, “seeks to provide a space in which the urban environment of Cork can be explored, questioned and discussed through the use of images, audio recordings and moving images.” Expect to find my images up there as soon as I get around to uploading them!
(Thanks Donal for pointing me at WMC and CorkSpace!)

autopano-sift: making panoramas fun

autopano-sift Looks like a great program for lining up panoramas. You need to use it alongside Hugin, Panotools and Enblend to stitch your photos together.
It’s a .net application written in C# so I’m glad I installed Mono last week!! There’s a great tutorial written by Rob Park that I’ll look over this weekend. I have a panorama of Kylemore Abbey to stitch together!

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