Webmin + Usermin on Debian etch mini-HOWTO

Webmin and Usermin are handy administration interface for system administrator, which cover a lot of daily duty for system administration, e.g. apache, bind9, dhcpd, webalizer, cron jobs, logrotate, etc. Some people don't suggest to use Webmin or Usermin due to security concern, but I seems it as a short cut for a newbie become professional. BTW, Debian etch no longer coming with official support of webmin/usermin package according to many reason (http://wiki.debian.org/Webmin?highlight=%28webmin%29), but the most important point is lack of package maintainer (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=343897). So you will not find webmin and usermin under both stable, testing and even unstable. Is the story end? Not yet! Official webmin/usermin website also provide debian package, which are most up-to-date! This mini-HOWTO will cover the required step for installing such 3rd party package into Debian etch.

Apache + HTTPS redirect on Debian mini-HOWTO

When will you need an automatically HTTPS redirection for your web service? Which means whenever client try to access the HTTP version, Apache will handle its redirection and forward them to HTTPS version. This technical is well known for most public web service which related to sensitives personal information, e.g. webmail, ebussiness, and epayment. This simple mini-HOWTO will guide you though this useful skill with Apache 2.2 and Debian etch.

KVM on Debian mini-HOWTO

A quick look about KVM (http://kvm.qumranet.com/kvmwiki/KVM-Wiki):
KVM (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware. It consists of a loadable kernel module (kvm.ko) and a userspace component. Using KVM, one can run multiple virtual machines running unmodified Linux or Windows images. Each virtual machine has private virtualized hardware: a network card, disk, graphics adapter, etc. The kernel component of KVM is included in mainline Linux, and will appear in Linux 2.6.20. KVM is open source software.
So how to set it up under Debian? Since KVM is still under active development, using Debian sid (unstable) would be a good idea; on the other hand, a VT supported CPU is also required; finally, you should have X11 installed. You may handle the setup of KVM client in many different way: manual command line parameter, custom pre-defined start/stop/config shell scripting, or by using libvirt + virt-manager. For this simple mini-HOWTO, I will guide you though the 1st solution with the least dependence.

Exim4 + ClamAV + SpamAssassin + Greylistd on Debian etch mini-HOWTO

What if you hope to have ClamAV and SpamAssassin with your Debian Exim4, but don't really hope for a complete virtual hosting email system with vexim? You may follow this simple guideline and set them up within 15min :)

Exim4 + Mailman + Apache2 on Debian etch mini-HOWTO

This is just a very fast and rough simple guideline for setting up Mailman + Exim4 based on Debian etch. For sure that we will also configure Apache2 for Mailman web interface. Not much detail will be mentioned, please refer to corresponding document if you hope to understand more. Debian also come with a handy guideline from /usr/share/doc/mailman/README.Exim4.Debian, so you should have a look with it before follow this guideline :)

DNS + DDNS + nsupate for dynamic IP web hosting on Debian mini-HOWTO

If you hope to host a static domain name, the process is quite straight forward: find a DNS provider, pay and register, provide 2 DNS server that will contain your domain information, and that's all. This shouldn't be a problem if you have 3+ static IP, so at least 2 for DNS server plus other for normal mapping. Well, as a normal Linux system administrator, this should be part of your daily jobs.

But what will happen if you don't have static IP? The case will be more complicated since you can't provide the required 2 static DNS server for redirect, and so the domain registration can't complete.

At this moment, you may think about free DDNS service, e.g. No-IP, DynDNS and so on. BTW, usually they only provide some free domain with not friendly DNS suffix (e.g. no-ip.info, no-ip.net, etc), which usually not your cup of tea...

So how to overcome these difficulties? Just combine both DDNS (take No-IP service as example), bind9 and nsupdate together. So finally, you will have a system with:

  1. Real DNS hostname. You will need this from anyone of DNS service provider; and for sure, you will able to register any name as you like if available.
  2. DDNS hostname for request redirect. This is just a fake name, in order to fake DNS service provider, and point the DNS NS request to our DDNS server.
  3. A Debian server that running bind9, noip2 and nsupdate. We will use the nsupdate toolkit to update our own bind9, about our current public IP. So this is a loop-back hack for bind9.
Sounds so tricky? Just take it easy, and I will guide you step-by-step :)

Server revamp with 3Ware 9650SE-8LPML!

Finally... Finally... I get the 3Ware 9650SE-8LPML for my server! Even the price of this card give me a bit of pain, the quality is need not to be question! A good BIOS UI, and I also get Debian's admin UI installed. Moreover, it is now able to fully utilize my new 9-bays server case (1 used for DVD) with hot swap plug-and-play supporting!

Howto find out which program opens tcp port?

For e.g. find out what opens port 3000:

lsof -i:3000

Display all PID and name of the program to which each tcp port belongs:

netstat -tlnp ps aux | grep 3000 ps -eo pid,user,args,pid --sort user

Original post: http://www.cyberciti.biz/motd-archive.php/15/find-out-which-program-opens-tcp-port/

PostgreSQL 8.1 + phppgadmin on Debian mini-HOWTO

The default installation of PostgreSQL in Debian etch is not yet well configured, and so not suitable to work with phppgadmin, too. This simple mini-HOWTO will guide you though those critical but minor procedures, which will let all of your PostgreSQL functioning within 5 min :)

VMWare rtc: lost some interrupts

You run VMWare Server on Debian Linux. You start a Guest OS, and suddenly your logs start filling up:

Aug 21 12:56:11 dey kernel: rtc: lost some interrupts at 2048Hz.

Aug 21 12:56:42 dey last message repeated 1528 times

Aug 21 12:57:43 dey last message repeated 3050 times

Aug 21 12:58:44 dey last message repeated 3050 times

VMWare is being a little too aggressive about checking the clock.


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