Poison for you mail server: virus scanning - Update

Sunday, 5. August 2007 22:07 - daniel - Server - 0 Comments


I'm running spamassassin + clamav on my server to filter spam and virus emails. This is pretty effective and keeps my inbox nearly 100% clean. But this also has some downsides. Over the last few days I received hundreds of email bounces. Everyone of these messages is passed through the scanners. The result was a 14 hour email queue and a load of nearly 2 on my 2500+ AMD Athlon box. Since that box is also used as a webserver I had a problem. The solution was to disable clamav.

Without clamav parsing every message, the quese was gone within minutes and the load dropped to a normal value. I have no idea why clamav needs that much processor time, but if you have load problems on you system with a similar setup, consider disabling the anti virus scanner.

[Update Oct. 21, 2007]
You can avoid this by using clamav-daemon instead a direct call to clamav. Syscp's default is a direct call to clamav. Not very clever if you ask me.



Howto filter mail bounces with Thunderbird

Sunday, 5. August 2007 19:33 - daniel - Other - 0 Comments


My domain www.tac-ops.net is used by spammer to send usolicited bulk email (UBE), mostly stock spam. Just to make this sure: I'm not responsible for this, they forge the FROM header to make it look like that a user with a @tac-ops.net email address send this emails. Of course no one is using this box to send UBE, if you don't believe me, just look at Recived headers of the email and compare it to the DNS entry of tac-ops.net.

Anyway, since I want to use catchall for some reason, I receive large amounts of bounces from MTAs that can't deliver the mails because the user don't exist. If you look at the source code of a bounce message, you should fine a line like this:

Content-Type: multipart/report; report-type=delivery-status;
Most MTAs use this Content-Type for bounces. Now we have to create a filter. Go to Tools -> Message Filters. A new window pops up. Click New to create a new filter and enter a Name you like. Instead of "Subject" you have to select "Customise". Now write "Content-Type" in the input filed, press "Add" and then press "OK".



Now select "Content-Type" from the list. In the next list select "contains" and write "multipart/report; report-type=delivery-status;" in the last field. In the "Perform these actions" area you can e.g. select to delete this messages, or move them to another folder.



This should filter most of the bounces you'll receive.



freewlan svn nightly builds properly building now

Tuesday, 31. July 2007 18:03 - daniel - Other - 0 Comments


A small mistake in my crontab file prevented the daily build from getting created. Everything is working now, so you should get your updates at midnight from now on.



freewlan.info addons nightly builds

Friday, 27. July 2007 9:15 - daniel - Other - 2 Comments


Nightly builds for the freewlan.info addons are now available from the official update server. You need the latest stable version (0.8.6) installed and preferable a serial cable if anything goes wrong.
Just type this line into the diagnostics page and you'll get the latest subversion build every night.

cat /etc/config/autoupdate | sed 's/stable/subversion/g' > /etc/config/autoupdate
But be aware that this can brick your Fonera. The subversion build may contain untested or unstable code. I don't take responsibility if anything goes wrong. In the worst case you have to reflash the Fonera to get it working again. If you don't have a serial cable, you should at least enable redboot access over ethernet.

Because a lot of files are downloaded and copied, the update can take quite some time to install. If the update is successful, the device will reboot and you should have a Fonera with the latest svn trunk.

The latest subversion snapshot is uploaded every day at midnight (0:00 CEST). If there are no updates in the svn repository, there isn't a update either.



mp3player parts

Wednesday, 25. July 2007 10:35 - daniel - Other - 0 Comments


Today I finally received the parts for the mp3player project a friend and I are working on. It's an ATmega16/VS1011 based embed device for a local company. With the parts here I hope to have a working development kit ready in a week or two. Until now I wasn't able to test the code I've written so far.

Additionally, I got informed that I'll soon receive another embed device where I have to write a small webserver app to display data that has been captured by the device. More to come when I have it here.