CUPS mini-mini-HOWTO – handy docs on configuring a printer using CUPS. The web-based interface is rather nice!
Category Archives: Linux
Can you hear me? Ping? Linux, ALSA, Via 82xx and 7.1 Surround Sound
I’ve finally got some sort of surround sound going, but only by clicking a “duplicate front” button in alsamixer. There are still 3 speakers that I can’t hear a peep from!
It wasn’t plain sailing in Windows either! For an age I couldn’t hear anything from the back-speakers but after replacing the 3->4 cable that came with the speakers with an old 3->3 cable plus another, it worked. I’ll look at it later again.
Here’s some links for reference:
Securing your Environment – LAMP firewall builder
Linux AMD64 Cool n Quiet support
According to this thread on kerneltrap, the Cool n Quiet features of AMD64 CPUs is supported by Linux! I’ll have to investigate. This machine is louder than anything else in the house!
Software Patents Adopted in EU
vfat (Very Fat?) Linux
This article is a good read if you access Windows/DOS drives from Linux. The author explains how to access those drives, as well as some of the restrictions and problems when using vfat drives.
NTFS is also an option of course, but as Linux only has read-only access to that, vfat is a better solution if you want to share files between the two operating systems. Pity it’s so slow and has so many restrictions. 🙁
There’s also a warning contained within: if you’re using a Linux 2.4 kernel, be wary if you have vfat partitions over 130GB in size. You will lose data. This problem was solved in the now widely available 2.6 kernel.
Looking good: Monitor calibration under X
This is a surprise to me, this article describes Monitor calibration in X. I haven’t looked at calibrating my monitor but it’s something useful I must try later.
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!
ATI Cards and Corrupted Text
This is new to me, but according to these setup tips my “Fixed Frequency Monitor” can’t handle the frequencies bandied about by my new ATI graphics card. It’s mildly annoying and sounds like a bit of a cop out as I haven’t seen anything similar on lower end cards!
When you’re in DOS mode or text mode and If you notice slight flickering around some characters, particularly “r”, then this could be the problem. The only solution is to upgrade your monitor or shut your eyes until you boot into a graphical GUI!
I wonder if that explains the following strange character corruption that appears during bootup:
Oh, Debian testing detects SATA drives without a hitch. 🙂
Later… Even in the GUI there’s corruption. Does this happen to other Radeon 9×00 users? The multi-colour lines in the image below appear randomly but seems to be worse when high-contrast web pages are displayed. This happens when using either the proprietary driver from ATI or the open source one in XFree86. Time to get on to Elara again.
Later Still… Opinion on #linux on irc.linux.ie is that the graphics card is damaged as 6 others who have ATI Radeon 9000 series cards have had no problems. I faxed them a return form 20 minutes ago and am waiting a response now.
Can I run Windows viruses in Linux?
It’s almost possible, but the results in this article on running Windows viruses with Wine are disappointing. There are problems but things are improving so Linux users can enjoy all the benefits of Windows!
It just isn’t fair that Windows users get all the viruses. I mean really, shouldn’t Linux users be in on the fun as well? Well… thanks to the folks running the Wine project, Linux users can “catch the virus bug” too — sort of.