Access your server from the outside world with a dynamic IP-addres

Posted in Debian, English tutorials, Latest news on March 8th, 2011 by yokke

Difference between a static and a dynamic IP

An IP address is used to communicate between computers. When a server has a static IP this will never change unless someone decides to. This IP is manually entered in the computer or server.An example of who uses a static IP is a web server. Every domain name has a web server, every public web server has an static IP.  For example www.google.com has the static IP  74.125.230.112 this IP will never change unless Google decides to move the web server to an other location. Because it isn’t possible to learn every IP-address on the internet we invented DNS (Domain Name System). How DNS works I’ll explain in one of my following tutorials for now just remember that DNS will resolve a domain name to the IP of the server.

What are the advantages and disadvantages of a static IP distribution

Advantages:

  • You can learn the IP
  • You can host a web server

Disadvantages

  • You need to configure an IP on each computer
  • You need to remember which IP-addresses are already used in your network

What are the advantages and disadvantages of Dynamic IP distribution

90% of the computers use a dynamic IP. This IP is distributed by a DHCP server.

Advantages

  • You don’t have to configure an IP manually
  • You can use Dynamic Domain Named Services to find your computer

Disadvantages

  • You need an DHCP server
  • You need to configure reserved addresses for printers etc
  • You don’t now which IP belongs to which computer unless you use DNS

So how do I solve my problem when my ISP gives me a dynamic IP and I want to contact my personal server from the world wide web?

Well, I’m going to explain this for my own ISP (also the router settings, this can be different on your router).

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Easy backup method for a Linux server

Posted in Debian, English tutorials, Latest news on February 20th, 2011 by yokke

Do I need backup?

Off course you need to backup your data! If you don’t have backups, you don’t have data security!

Depending on the value of your data you will need to make more backups or keep them longer or whatever. You should always ask yourself the question what if I lose all my data? Which data is extremely important.

You can make a backup of various data, for example:

  • The operating system
  • The storage server (RAID 5 = NO BACKUP!)
  • Mail server
  • SQL server
  • Web server

When you lose a server or its data you should be able to restore your data in a few hours. You can’t make it to lose all your data. When you are working in a professional environment you will notice that there is a backup plan (if not create one!). This plan indicates how often backups should be made and where they are stored.

When you make a backup never save this on the same disk as the original disk. If you do this, in case of a disk failure you will lose all your data + all your backup data. Therefor its important to have a backup disk or a backup server.

Backup is very important but whats even more important is the restore procedure. In case of a failure you will rely on your backups and you need to restore everything.

You should test if your backups work, test if they still work after you restored them. At least once each year you should test if your backup & recovery plan is working. By testing it, you will be familiar with the procedure and its problems. You can also indicate the time it takes to be up & running again. (Your management will demand answers when things go wrong, be prepared!)

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Server network statistics

Posted in Debian, English tutorials, Latest news on February 15th, 2011 by yokke

When you build a network, over time this network will grow. This is why it’s important to keep statistics. So you can expand before you run out of space or bandwidth.

Under Linux there are a few ways to do this. One of them I’m going to explain today.

The program I’ve found on the internet doesn’t do anything more than monitor your network traffic. The program runs under every Linux distribution.

At the beginning of this tutorial I would like to say that this is just a basic tool. Later on I will provide a detailed tool that uses snmp to make statistics.

In this tutorial I’m going to demonstrate how you can install vnStat under Debian 6.0.

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