Showing posts with label systems | network. Show all posts
Showing posts with label systems | network. Show all posts

Friday, January 14, 2011

Backtrack - Cracking WEP UPDATE

In this episode of Full Disclosure, Nox and I describe four improved methods of cracking WEP encryption: the ARP Request Replay Attack, Fragmentation Attack, Caffe Latte Attack, and Hirte Attack. The ARP Request Replay Attack and the Fragmentation Attack are known as clientless attacks because they do not require a client to be connected to the wireless AP. To initiate the attack, these two attacks only require one data packet. The Caffe Latte Attack and the Hirte Attack are client-based attacks because they specifically target clients to increase the IVs. Also, we show an improved method of cracking the IVs called the PTW cracking method. With the PTW method, WEP encryption can be cracked 80% of the time with only 60,000 IVs.

Live Streaming
Download

Source: http://infinityexists.com/

Mark Achel Gagalac

How to Optimize Windows 7 Desktop

Here's my personal tips and tweaks to get the best performance of your Windows 7 desktop.

1) Editing the performance options

- Right Click on My Computer then choose Properties.
- Click on Advanced system settings.
- In the Advanced tab under Performance, Click on Settings and choose the "Adjust for best performance".
- Click Apply and hit OK.

2) Tweaking the boot configuration and the system services and startup via msconfig

- Open the RUN command, and type in msconfig
- Click on the Boot tab, edit the Timeout seconds to 3 and click on Advanced options.
- Put the max processor available in the Number of processors options and alot full memory in the Maximum memory option and hit OK.
- Click on the Services tab and check the Hide all Microsoft services.
- You can uncheck everything or just choose the application services you need and click on Apply.
- Click on the Startup tab and click on Disable all. Click on Apply and hit OK.
- Reboot!

After reboot, You will notice that your system is a lot faster than it was before or even small difference but result is actually different. :)

Mark Achel Gagalac

Thursday, January 13, 2011

Forgotten root Password - Fedora / CentOS

You can log in using single-user mode and create a new root password.

To enter single-user mode, reboot your computer. If you use the default boot loader, GRUB, you can enter single user mode by performing the following:

   1. At the boot loader menu, use the arrow keys to highlight the installation you want to edit and type [A] to enter into append mode.

   2. You are presented with a prompt that looks similar to the following:

      grub append> ro root=LABEL=/

   3. Press the Spacebar once to add a blank space, then add the word single to tell GRUB to boot into single-user Linux mode. The result should look like the following:

      ro root=LABEL=/ single

   4. Press [Enter] and GRUB will boot single-user Linux mode. After it finishes loading, you will be presented with a shell prompt similar to the following:

      sh-2.05b#

   5. You can now change the root password by typing

      passwd root


Here is my step by step screenshot resetting my own root password.

step 1
step 2
step 3
step 4
step 5
step 6

Enjoy!

Mark Achel Gagalac

Top Tips for Importing & Exporting your VM with Hyper-V

As you accumulate virtual machines, then sooner or later you are probably going to run into a situation in which you want to move one or more virtual machines to a new host server. Microsoft makes this possible through the Hyper-V Manager’s Import and Export functions.

If you look at Figure A, you can see that  when you select a virtual machine, Hyper-V displays an Export link in the lower right corner of the console. There is also an Import Virtual Machine link at near the top of the Actions pane.

Figure A

The Import and Export functions are accessible through the Hyper-V Manager.

On the surface, it appears that you can simply select a virtual machine, export it, take the exported image to another server that’s running Hyper-V, and import it. On some levels this really is the way that the import and export processes work. There are some gotchas that you need to be aware of though, and the only way that you can avoid those gotchas is to understand what’s really going on when you export and import a virtual machine.

Virtual Machine Identification

The first thing that you need to understand about the import and the export process is that Hyper-V has two different ways of identifying virtual machines. The most obvious way of identifying a virtual machine is by the name that you have assigned to it. For example, if you look back at Figure A, the Actions pane will show you that I have selected a virtual machine named Posey-IM. Virtual machines retain their name throughout the import and export process. Although it is certainly advisable to avoid having multiple virtual machines with the same name, it is not an absolute requirement.

The reason why virtual machine names do not absolutely have to be unique is because there is a second factor that identifies a virtual machine. This second identification factor is the virtual machine’s Globally Unique Identifier, or GUID, which is automatically assigned to a virtual machine by Windows, and does have to be unique.

The Virtual Machine Export Process

The virtual machine export process itself is actually really simple to perform.  Simply select a virtual machine from the Hyper-V Manager, and then click the Export link. After doing so, Windows will display the Export Virtual Machine dialog box that is shown in Figure B. All you have to do now is to enter the path that you want to export the virtual machine to, and then click the Export button.

Figure B

The process of exporting a virtual machine is really simple.

So what’s so tricky about the export process? Well, not a lot really, but there are still some things that you need to know about it. For starters, Windows will place the virtual machine within a sub folder that bears the virtual machine’s name within the path that you have specified. For example, I decided to export a virtual machine named R2. Not wanting to lose the files among other clutter, I created a folder named C:\R2 and specified that as the export path. What I ended up with was the exported files residing in a folder named C:\R2\R2\.

One of the big questions that I had about the export process before I began was whether or not it left the original virtual machine instance intact, and in its original location. I’m happy to report that the files making up the virtual machine are untouched during the export process. This does however, mean that you will have to manually remove those files once you have moved the virtual server to its new location.

The other thing that you need to know is that depending on the size of the virtual machine, the export process can take a really long time to complete. Unfortunately, I can’t tell you exactly how long, because the amount of time depends on the size of the .VHD files that are being used, and on your machine’s hardware capabilities.

As you can see, exporting a virtual machine is really simple. Now let's take a look at the anatomy of the exported information, and how the import process works.

The Anatomy of a Virtual Machine

When you export a virtual machine, one of the things that Hyper-V asks you for is the export path. Whatever path you enter, Hyper-V will create a folder in that path that bears the name of the virtual machine that you are exporting. For instance, when I exported my virtual machine, I used C:\R2 as the path, and Hyper-V created a new folder named R2. Now my virtual machine resides in a folder named C:\R2\R2, as shown in Figure C.

Figure C

Hyper-V creates a folder in the destination path that bears the name of the virtual server that you are exporting.

If you look at the figure, you will notice that within the folder that Hyper-V creates are three sub folders. There is also an XML file named Config.xml.

The Snapshots Folder

The Snapshots folder is used as a repository for snapshots of the virtual machine. This folder contains three elements. First, there is a subfolder that bears the virtual machine’s GUID. If no snapshots exist, the folder will still be present, but it will be empty. If snapshots do exist, then this folder will contain the diffing data for the virtual hard disks.

The snapshots folder may also contain a subfolder for each snapshot. This folder bears the name of the individual snapshot ID. In addition, there will be an export file (a .EXP file) for each individual snapshot.

The Virtual Hard Disks Folder

As the name implies, the Virtual Hard Disks folder stores the .VHD files (virtual hard drive files) used by the virtual machine. You can see an example of this in Figure D.

Figure D

The Virtual Hard Disks folder contains the .VHD files for the virtual server.

The Virtual Machines Folder

At a minimum, the Virtual Machines folder will contain a file named after the virtual machine’s GUID, but with an .EXP extension. This file is the virtual machine export file. It retains the virtual machine’s settings during the export process.

If the virtual machine was in a saved state during the export process, then the Virtual Machines folder will contain a sub folder, which will store two saved state files. If the machine was not in a saved state at the time of the export, then the sub folder may exist, but it will be empty.

Importing a Virtual Machine

The import and export process is used primarily as a means for moving virtual machines from one host server to another. Therefore, the first step in the import process is to copy the export folder and all of its sub folders to the desired host server.  After doing so, open the Hyper-V Manager and click the Import Virtual Machine link. You should now be prompted to enter the virtual machine’s path.

Although this seems simple enough, there are two very important There are two important things that you need to know about the import process. First, it is up to you to copy the virtual machine files to the location from which you want to use them. When you import the virtual machine, it’s physical location on the host server becomes permanent, and moving the virtual machine is no longer an option. It is therefore important to place the virtual machine files on the desired volume before you import it.

The other thing that you need to know is that when you import the virtual machine, the .EXP file and the CONFIG.XML files will be deleted. These files are replaced with a new CONFIG.XML file. What this means to you is that because the .EXP file is gone, the virtual machine cannot be imported again (unless you export it again). If you want to use the virtual machine as a template or as an image that you can quickly restore, then it is important to work only from a copy of your exported files so that the original remains untouched.

Conclusion

The process of importing and exporting virtual machines isn’t all that difficult, but by following these tips, hopefully you'll save yourself from a few of the most common pitfalls related to duplicate virtual machines or the imported machine’s location.

Source: http://www.petri.co.il/importing-and-exporting-your-virtual-machines.htm

Saturday, January 1, 2011

Increase bandwidth by tweaking QoS in Windows XP Pro

The following tweak applies only to Windows XP Professional edition.

The default system behavior is that all 100% bandwidth is available, however, if there is a running application that indicates to the OS it needs to send high priority/real time data, then as long as it has the socket open, Windows XP will restrict “best effort” traffic to 80% of the bandwidth so that high priority traffic can be accommodated. Basically, applications can make this request to the operating system for QoS support using the QoS application programming interfaces (APIs) in Windows and this only applies if a specific app is requesting QoS.

If you'd like to change how much bandwidth is reserved for QoS (the default is 20% of the total bandwidth), do the following:

1. Make sure you're logged in as "Administrator" (not just any account with admin privileges).
2. Navigate to START>Run and type: gpedit.msc
3. Navigate to Local Computer Policy > Administrative Templates > Network > QOS Packet Scheduler
4. In the right window, double-click the limit reservable bandwidth setting
5. On the setting tab, check the enabled setting.
6. Where it says "Bandwidth limit %", change it to read 0 (or whatever percentage you want to reserve for high priority QoS data)
7. Click OK, close gpedit.msc

Under START > My Computer > My Network Connections > View Network Connections, right-click on your connection and under Properties (where it lists your protocols), make sure QOS Packet Scheduler is enabled.



The tweak desribed below helps boost priority for DNS & hostname resolution in general. What this means is, it helps web pages load faster, and has negligible effect on downloads (not counting the couple of ms gain with the host resolution at connect-time).

Applying this tweak assumes some proficiency in editing the Windows Registry using Regedit (Start > Run > type: regedit). As always, backup your Registry before making any changes so you can revert to the previous state if you don't like the results.

Wednesday, December 29, 2010

Basic Linux Commands

These commands will work with most (if not all) distributions of Linux as well as most (?) implementations of Unix.

Communication
ftp – File Transfer Protocol.
login – Sign on.
rlogin – Sign on to remote system.
rsh – Run shell or single command on remote system.
talk -Exchange messages interactively with other terminals.
telnet – Connect to another system.
tftp – Trivial file transfer protocol.

Comparisons
cmp – Compare two files, byte by byte.
comm – Compare items in two sorted files.
diff – Compare two files, line by line.
diff3 – Compare three files.

File Management
cat – Concatenate files or display them.
chfn -Change user information for finger, email, etc.
cksum – Compute checksum.
chmod -Change access modes on files.
chsh – Change login shell.
cp – Copy files.
csplit -Break files at specific locations.
dd -Copy files in raw disk form.
file – Determine a file’s type.
head – Show the first few lines of a file.
less – Display files by screenful.
ln – Create filename aliases.
ls – List files or directories.
merge – Merge changes from different files.
mkdir -Create a directory.
more – Display files by screenful.
mv – Move or rename files or directories.
newgrp – Change current group.
pwd – Print working directory.
rcp – Copy files to remote system.
rm -Remove files.
rmdir -Remove directories.
split – Split files evenly.
tail – Show the last few lines of a file.
wc – Count lines, words, and characters.

Sunday, December 12, 2010

Remote Server Administration Tools for Windows 7

Remote Server Administration Tools for Windows® 7 enables IT administrators to manage roles and features that are installed on computers that are running Windows Server® 2008 R2, Windows Server® 2008, or Windows Server® 2003, from a remote computer that is running Windows 7.

Here's the link:
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=7d2f6ad7-656b-4313-a005-4e344e43997d&displaylang=en

Enjoy!

Friday, December 10, 2010

Linux Integration Services v2.1 for Windows Server 2008 Hyper-V R2

I tried to google a tool and a way to make a linux or redhat based system run on Hyper-V and finally I found a good one.

A set of drivers that enable synthetic device support in supported Linux virtual machines under Hyper-V.

Here's the Link:
http://www.microsoft.com/downloads/en/details.aspx?displaylang=en&FamilyID=eee39325-898b-4522-9b4c-f4b5b9b64551

Thursday, December 9, 2010

PHP Point Of Sale Installation Guide on CentOS 5.5

download the latest release of php point of sale here:
http://www.phppointofsale.com/downloads.php

extract and upload it to your /var/www/html folder

rename the folder to pos

login to shell

install additional software needed

yum install httpd
yum install php
yum install mysql
yum install php-mysql
yum install php-devel
yum install php-pear
yum install gcc
pear install pecl/json

cd /etc/php.d
echo "extension=json.so" > json.ini

reboot

mysql -u root -p
create database pos;
grant all on pos.* to posuser@localhost identified by 'pospassword';
flush privileges;
exit

import the database

mysql -u root -p pos < /var/www/html/pos/database/database.sql -v
cd /var/www/html/pos/application/config
cp database.php.tmpl database.php
vi database.php

fill up the database info and save it.

you're done.

Saturday, December 4, 2010

ZoneMinder 1.24.2 Installation Guide on CentOS 5.5

Most of this is taken from the zoneminder wiki, others from various posts on their forums. I put them all together and this guide works 200%. This guide serves as my cheat sheet and have implemented in several machines. Goodluck!

---

1) yum update then reboot

2) Setup -> Firewall -> disable Security Level and SELinux

3) Disable the following services and then reboot...
apmd
bluetooth
cups
hidd
ip6tables
iptables
netfs
nfslock
pcscd
portmap

4) Add RPM Forge REPO
rpm -Uhv http://apt.sw.be/redhat/el5/en/i386/rpmforge/RPMS/rpmforge-release-0.3.6-1.el5.rf.i386.rpm

5) Install software needed for ZM Installation:
yum -y install mysql mysql-server mysql-devel php php-gd php-mysql httpd gcc pcre-devel gd mod_ssl glib2-devel gcc-c++ ntp gnutls-devel ImageMagick libjpeg-devel perl-Archive-Tar perl-MIME-Lite perl-MIME-tools perl-Date-Manip perl-LWP-UserAgent-Determined perl-PHP-Serialization perl-Device-SerialPort perl-Archive-Zip perl-Sys-Mmap.i386 perl-Module-Load subversion git screen yasm

6) Confirm installation and then reboot.

7) Install ffmpeg
rpm -Uvh http://apt.sw.be/redhat/el5/en/i386/rpmforge/RPMS/rpmforge-release-0.5.1-1.el5.rf.i386.rpm
yum install ffmpeg ffmpeg-devel

8) Turn on services:
chkconfig httpd on
chkconfig mysqld on
chkconfig ntpd on
ntpdate pool.ntp.org
service httpd start
service mysqld start
service ntpd start

9) Setup your MySQL:
/usr/bin/mysql_secure_installation

10) Download and extract ZM files:
cd /root
wget http://www2.zoneminder.com/downloads/ZoneMinder-1.24.2.tar.gz
wget http://www.zoneminder.com/fileadmin/downloads/cambozola.jar
tar -zxvf ZoneMinder-1.24.2.tar.gz
cd ZoneMinder-1.24.2

11) Install
CXXFLAGS=-D__STDC_CONSTANT_MACROS ./configure --with-webdir=/var/www/html/zm --with-cgidir=/var/www/cgi-bin --with-webuser=apache --with-webgroup=apache ZM_DB_HOST=localhost ZM_DB_NAME=zm ZM_DB_USER=zmuser ZM_DB_PASS=yourpassword
make
make install

12) MySQL Preparation:
mysql -u root -p
create database zm;
grant all on zm.* to zmuser@localhost identified by 'yourpassword';
flush privileges;
exit

13) Import the Database:
cd /root/ZoneMinder-1.24.2
mysql -u root -p zm < db/zm_create.sql

14) Finale
cp scripts/zm /etc/init.d/
chmod +x /etc/init.d/zm
chkconfig zm on
cd ..
cp cambozola.jar /var/www/html/zm/
chown apache:apache /var/www/html/zm/cambozola.jar
service zm start

--

and you're done! kindly check the wiki / documentation for option properties. adding cams, adjusting this and such..

Mark

Saturday, October 23, 2010

Setting IP address in Backtrack 4

These are my step to set ip address:

1. Open Konsole.

2. Type "ifconfig eth0 192.168.1.5" and press "enter" (this mean we set ip address 192.168.1.5 for ethernet card)

3. Type "route add default gw 192.168.1.1" and press "enter" (this mean we set default get way 192.168.1.1 for this ethernet, and this is depend on our network)

4. Type "echo nameserver 202.134.0.155 > /etc/resolve.conf" and press enter (this mean we set dns server ip address with: 202.134.0.155, and this is depend on our ISP)

5. If finish we can check our connection by pinging our getway (in this example "ping 192.168.1.1") if this connection OK, we can see "64 bytes from 192.168.1.1: icmp_seq=1 ttl=254 time=0.961 ms" appear in our console. Time in ms depend on our network.

I hope this post can help others.

How to Start Networking in Backtrack

1. To start networking in Backtrack 4 final issue the following command.

/etc/init.d/networking start

This will attempt to start all the interfaces in the /etc/network/interfaces file.

root@bt:~# cat /etc/network/interfaces
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp

auto eth1
iface eth1 inet dhcp

auto eth2
iface eth2 inet dhcp

auto ath0
iface ath0 inet dhcp

auto wlan0
iface wlan0 inet dhcp

If you don't have or don't want some of these interfaces then simply remove the from this file and they will not start.

If you need to set a static IP just set the variables in the /etc/network/interfaces file

auto eth0
iface eth0 inet static
address 192.168.0.100
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
gateway 192.168.0.1

You will also need to make sure you set a nameserver in /etc/resolv.conf

root@bt:~# cat /etc/resolv.conf
nameserver 192.168.0.1

So for example if all you have is eth0 and wlan0 on your system and you want them both to get a adress via DHCP then remove every thing else for the file with the exception of the lo interface. Here is a example.

root@bt:~# cat /etc/network/interfaces
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp

auto wlan0
iface wlan0 inet dhcp


Now if are lazy and want all this to start at boot you can simply issue this command as root

update-rc.d networking defaults

This will create all the proper sym-links

What about ssh?

So while I am on the subject I may as well go over ssh. In order to use ssh on backtrack 4 final you need to generate the keys first.

sshd-generate

after that you can start ssh like this:

/etc/init.d/ssh start

or you can add it to the boot sequence like this:

update-rc.d ssh defaults

Well thats enough to get up and running. I hope this was somewhat helpful to any one just getting started with backtrack.

Sunday, August 22, 2010

PRTG Network Monitor

I was looking for a good network monitoring tool this past few weeks. I tried MRTG, Cacti, Bandwidthd and etch. Cacti seems to be one of the best graphing tool I've used and Nagios for alerts and etch.. But if you guys wants it easy way, You can use PRTG Network Monitor. It's very easy to setup and use but runs only in Windows Operating Systems. I suggest you give it a try.. heres the link:

http://www.paessler.com/prtg/

Monday, August 16, 2010

112 Windows run commands

Accessibility Controls
Add Hardware Wizard
Add/Remove Programs
Administrative Tools
Automatic Updates
Bluetooth Transfer Wizard
Calculator
Certificate Manager
Character Map
Check Disk Utility
Clipboard Viewer
Command Prompt
Component Services
Computer Management
Date/Time Properties
DDE Share
Device Manager
Direct X Control Panel (If Installed)*
Direct X Troubleshooter
Disk Cleanup Utility
Disk Defragment
Disk Management
Disk Partition Manager
Display Properties
Display Properties
Display Properties (w/Appearance Tab Preselected)
Dr. Watson System Troubleshooting Utility
Driver Verifier Utility
Event Viewer
File Signature Verification Tool
Findfast
Folders Properties
Fonts
Fonts Folder
Free Cell Card Game
Game Controllers
Group Policy Editor (XP Prof)
Hearts Card Game
Iexpress Wizard
Indexing Service
Internet Properties
IP Configuration (Display Connection Configuration)
IP Configuration (Display DNS Cache Contents)
IP Configuration (Delete DNS Cache Contents)
IP Configuration (Release All Connections)
IP Configuration (Renew All Connections)
IP Configuration (Refreshes DHCP & Re-Registers DNS)
IP Configuration (Display DHCP Class ID)
IP Configuration (Modifies DHCP Class ID)
Java Control Panel (If Installed)
Java Control Panel (If Installed)
Keyboard Properties
Local Security Settings
Local Users and Groups
Logs You Out Of Windows
Microsoft Chat
Minesweeper Game
Mouse Properties
Mouse Properties
Network Connections
Network Connections
Network Setup Wizard
Notepad
Nview Desktop Manager (If Installed)
Object Packager
ODBC Data Source Administrator
On Screen Keyboard
Opens AC3 Filter (If Installed)
Password Properties
Performance Monitor
Phone and Modem Options
Power Configuration
Printers and Faxes
Printers Folder
Private Character Editor
Quicktime (If Installed)
Regional Settings
Registry Editor
Registry Editor
Remote Desktop
Removable Storage
Removable Storage Operator Requests
Resultant Set of Policy (XP Prof)
Scanners and Cameras
Scheduled Tasks
Security Center
Services
Shared Folders
Shuts Down Windows
Sounds and Audio
Spider Solitare Card Game
SQL Client Configuration
System Configuration Editor
System Configuration Utility
System File Checker Utility (Scan Immediately)
System File Checker Utility (Scan Once At Next Boot)
System File Checker Utility (Scan On Every Boot)
System File Checker Utility (Return to Default Setting)
System File Checker Utility (Purge File Cache)
System File Checker Utility (Set Cache Size to size x)
System Properties
Task Manager
Telnet Client
User Account Management
Utility Manager
Windows Firewall
Windows Magnifier
Windows Management Infrastructure
Windows System Security Tool
Windows Update Launches
Windows XP Tour Wizard
Wordpad
access.cpl
hdwwiz.cpl
appwiz.cpl
control admintools
wuaucpl.cpl
fsquirt
calc
certmgr.msc
charmap
chkdsk
clipbrd
cmd
dcomcnfg
compmgmt.msc
timedate.cpl
ddeshare
devmgmt.msc
directx.cpl
dxdiag
cleanmgr
dfrg.msc
diskmgmt.msc
diskpart
control desktop
desk.cpl
control color
drwtsn32
verifier
eventvwr.msc
sigverif
findfast.cpl
control folders
control fonts
fonts
freecell
joy.cpl
gpedit.msc
mshearts
iexpress
ciadv.msc
inetcpl.cpl
ipconfig /all
ipconfig /displaydns
ipconfig /flushdns
ipconfig /release
ipconfig /renew
ipconfig /registerdns
ipconfig /showclassid
ipconfig /setclassid
jpicpl32.cpl
javaws
control keyboard
secpol.msc
lusrmgr.msc
logoff
winchat
winmine
control mouse
main.cpl
control netconnections
ncpa.cpl
netsetup.cpl
notepad
nvtuicpl.cpl
packager
odbccp32.cpl
osk
ac3filter.cpl
password.cpl
perfmon
telephon.cpl
powercfg.cpl
control printers
printers
eudcedit
QuickTime.cpl
intl.cpl
regedit
regedit32
mstsc
ntmsmgr.msc
ntmsoprq.msc
rsop.msc
sticpl.cpl
control schedtasks
wscui.cpl
services.msc
fsmgmt.msc
shutdown
mmsys.cpl
spider
cliconfg
sysedit
msconfig
sfc /scannow
sfc /scanonce
sfc /scanboot
sfc /revert
sfc /purgecache
sfc /cachesize=x
sysdm.cpl
taskmgr
telnet
nusrmgr.cpl
utilman
firewall.cpl
magnify
wmimgmt.msc
syskey
wupdmgr
tourstart
write

Rearm Windows from Evaluation Period

If your 30 days trial is about to expire, I found a good way to rearm it. I have learned this quirk and I just wanted to share. Here's how to do that:

1) Run your CMD as Administrator.
2) Type slmgr.vbs –rearm
3) Restart your system and smile. :P

If the above command didn't work, specially if you're using Windows 7, try:
slmgr.vbs /rearm

Have Fun! :)

Dynamic Versus Static IP Addresses

Here we describe dynamic and static IP addresses, and discuss the advantages and disadvantages associated with each type.

A.1 Dynamic IP (DHCP) Address

Each time a DHCP client boots, it sends out a DHCP discover message. All DHCP servers answer (in practice only one is set to do this at Fermilab; in the future possibly a second will be added for redundancy) with an offer message that includes an address which is available to the client.

The client machine typically repeats the discover message several times to make sure it hears from all the servers, then eventually chooses the "best" server, where what is "best" is up to the client. It may mean that the addresses the DHCP server has available offer the longest lease time. Or the client might prefer a server that provides WINS servers over one that doesn't (the WINS servers keep track of all the clients' and servers' latest dynamic IP addresses).

The currently active DHCP server is configured by hand to handle and reserve IP addresses and the IP configuration information that goes with them. Addresses are made available in an order that permits a client to have the best chance of getting back the same address it was using most recently. To this end, the DHCP server offers its least recently used address to a new client.

Once the client chooses a DHCP server, it "officially" requests the IP address and configuration information. In addition to this, it receives a lease time for the address. This lease time is not absolute. As long as it is running, the client machine requests renewal of the lease. This is invisible to the user, although there is a mechanism for the user to release the address early ( ipconfig/release from the command prompt).

Client machines in the NT domain typically access multiple file servers, print servers, and so on. The clients as well as the servers may change their IP addresses. Via the WINS servers, this is transparent to the user.

Advantages

1. All the IP configuration information gets automatically configured for your client machine by the DHCP server.
2. If you move your client machine to a different subnet, the client will send out its discover message at boot time and work as usual. However, when you first boot up there you will not be able to get back the IP address you had at your previous location regardless of how little time has passed.

Disadvantage

Your machine name does not change when you get a new IP address. The DNS (Domain Name System) name is associated with your IP address and therefore does change. This only presents a problem if other clients try to access your machine by its DNS name. One example is ftp . If a Windows machine is set up as an ftp server, then its ftp server name (which uses the DNS name) changes every time the IP address does. If you need to use your Windows machine as an ftp server (or as a Web server), request a static IP address rather than a dynamic one.

A.2 Static IP Address

Advantages

1. The two names (Windows name and DNS name) are the same as each other, and neither ever changes. Other clients may therefore reliably access your machine by its DNS name (e.g., using ftp ).
2. With a static address your machine is more easily accessible by non-Windows internet services. This is not a significant advantage as people seldom telnet to their Windows PC.

Disadvantages

1. You can't move your machine to a different subnet and expect it to work. You need to reconfigure it.
2. If machines come and go, or are up only some of the time, static assignments are less resource-efficient (where the resource in question is the IP address itself).


SOURCE: http://www.fnal.gov/docs/pc/nt_at_fermilab/html/current/ntguide.b.html