networked day to day technical issues

27Mar/112

Running Linux on Sparc hardware

I have a SunFire V210 laying around, which i bought in order to learn Solaris and get accustomed to it's hardware platform.

Now i need to move a personal project from it's current server to another one and i though that i might put to use the Sun server to use. It turns out that not that many people run Linux on the Sparc architecture and some things that i expected to work (like software raid) turned out to be complicated to set up.

Linux Distribution - basically you have two options if you're looking for an up to date and maintained distro: Debian or Gentoo . When i first installed this server (few months ago) Squeeze was not out and because i was looking for something which has newer software i decided to go with Gentoo despite the fact that i don't like compiling everything over and over and over again.

Linux Software Raid - there isn't a good place to find relevant information so i had to read a lot through discussion lists, forums and blogs until i got it working as expected ; after i finished my setup Debian Squeeze was released and the installer does help a lot.

23Mar/110

How to find out all of the ip addresses of an Europe based ISP

You may want to block ip traffic from a particular Internet Services Provider due to different reasons , like for example a lot of crawlers and spammers are hosted there.
For Europe based providers this can be done querying RIPE NCC database : "The RIPE Database contains registration information for networks in the the RIPE NCC service region and related contact details" . This is something which can't be avoided and the data there is genuine.

To query either use the web interface or better the whois Linux/*nix command line client. For this you need to already know the AS (Autonomous System) number for that provider and this can be easily established if you know an ip address from that particular provider

$ whois -- yyy.yyy.yyy.yyy | grep '^origin:' | awk {'print $2'}
ASxxxx
$ whois -h whois.ripe.net -- -i or ASxxxx | grep '^route:'| awk {'print $2'}
11Mar/111

Linux: realtime traffic monitoring and path determination

There are situations when one needs to give the answer to questions like:

- a) - what application/process is listening for inbound connections
- b) - what application/process is causing network traffic
- c) - what hosts are right now doing network traffic with our server
- d) - current rate of traffic going through the network interfaces
- e) - how much traffic is causing each workstation/server directly connected to the Linux server
- f) - which path is an outgoing packet going to take when you have multiple network cards and several routes (and more than one routing tables)