How to fix an IP address conflict?

Ever get the following message when turning on your computer or taking it out of sleep mode?

“There is an IP address conflict with another system on the network”

You may also see a different error message for the same problem:

“This IP address is already in use on the network. Please reconfigure a different IP address.”

This occurs when two computers on the same LAN network end up with the same IP address. When this occurs, both computers end up not being able to connect to network resources or perform other network
operations.

This problem, though rare, can occur because of the following reasons:

1.Two computers are assigned the same static IP addresses

2.One computer is assigned a static IP address that falls into the DHCP range for the local network and the same address is assigned to a computer by the DHCP server

3.A laptop is put into sleep mode and then turned on while connected to another network that uses the same IP address

4.If you have multiple network adapters, it is possible for a to have an IP address conflict with itself

How to resolve an IP address conflict:

There are a few ways you can go about fixing this problem. I’ll start with the simplest and move on.

1. Renew IP Address – You can release and renew the IP address for your computer using the command prompt. Read my previous post on how to renew an IP address.

2. Reconfigure Static IP Address – If your computer is using a static IP address, it is best to try and use a different one in the same subnet. One way to check to make sure the one you are picking is not already being used is to simple ping the IP addresss (ping x.x.x.x).

3. Use DHCP – If you don’t need to use a static IP address, it’s best to simply choose DHCP instead of manually configuring the IP address. The server will know which addresses are free and which are taken.

4. Update firmware – In some rare instances, the actual DHCP server can malfunction and assign more than one computer the same IP. In this case, it is best to try and update the firmware on your router.

How To Find Out What My DNS Servers Address Is?

How do I find out my DNS Server Addresses under Linux / UNIX / Windows operating system? What is my dns server IP address under Windows operating systems? Can you specify a list of public DNS server for personal use or game consoles?

DNS is key to many network services. Internet browsing, mail server, web server etc all depends upon DNS server. Most ISP (Internet service provider) have their own caching dns server to reduce network load. But how do you find out DNS server IP address? How do you find out current DNS server IP address? Under Linux, FreeBSD and all UNIX like oses you have file called /etc/resolv.conf file. It is often know as resolver configuration file. If you are using MS-Windows version Vista / 7 / NT / 2000 / XP /98 etc then see below for how to find out DNS server address under MS-Windows operating systems.

Linux / UNIX / Apple OS X Find Out Dns Server Addresses:

The resolver is a set of routines in the C library that provide access to the Internet Domain Name System (DNS). The resolver configuration file contains information that is read by the resolver routines the first time they are invoked by a process.

Commend to find out your dns servers ip address under Linux/BSD/Unixish system

To see your DNS server address type following command as shell prompt:

$ cat /etc/resolv.conf

OR

$ less /etc/resolv.conf

nameserver 203.54.1.20
nameserver 203.54.1.21

Where,

nameserver 203.54.1.20 : It is Name server IP address (in dot notation) of a name server that the resolver should query. All your application will use this IP address for DNS purpose.Where,

Find Out DNS Server IP Address Under MS-Windows Version 7/Vista/XP/NT/2003

Click on Start button > Run > and Type command cmd > Press [enter] key

At DOS prompt type the command:

C:\>ipconfig /all

You should DNS server IP address, and other information related to Windows networking:

OR
You can Click on Start button > Settings > Network connections
Double click on Local Area Connection
Click on Properties button
Select Internet Protocol (TCP/IP)
Click on Properties button and Look for Preferred DNS Server:

You Can Use The Public DNS Servers:

You can use the following Google public DNS (IP Addresses) servers for XBOX 360 / Sony PS3 & PS2 / Nintendo Wii game consoles or any other purpose:

8.8.8.8
8.8.4.4
They are free to all, pretty fast too and works with all sort of computers and game consoles.You Can Use The Public DNS Servers

Free DNS Server:

OpenDNS Free DNS Server IP address

=> 208.67.222.222
=> 208.67.220.220

ScrubIT Free DNS Server IP address

=> 67.138.54.100
=> 207.225.209.66

How do I setup DNS Server IP address?

Under Linux / UNIX / Solaris / BSD operating systems, just open your /etc/resolv.conf file and add above IP address:

nameserver 208.67.222.222
nameserver 208.67.220.220

How To: Find IP Address Owner Via Terminal

I’m getting lots of spam from few IPs. How do I find the owner of an IP address and report them to concern parties?

All public IP address on the Internet is registered to ISP or an owner or a larger organization. Each IP address is recorded in the whois database. You can query this database to get owner name, phone, email address and so on the Internet using whois command line client.

Find IP Address For A Host Name

For instance to find the IP address for a http://www.firstplanet.in open a command line and type in:

host www.firstplanet.in

or

nslookup www.firstplanet.in

Sample output:

http://www.firstplanet.in is an alias for firstplanet.in.
firstplanet.in has address 174.37.118.32
firstplanet.in mail is handled by 0 firstplanet.in.

whois – Client For The Whois Directory Service

Type the following command to find out the owner of an IP address called 74.86.48.99:

$ whois 74.86.48.99

Sample Outputs:

OrgName:    SoftLayer Technologies Inc.
OrgID:      SOFTL
Address:    1950 N Stemmons Freeway
City:       Dallas
StateProv:  TX
PostalCode: 75207
Country:    US

ReferralServer: rwhois://rwhois.softlayer.com:4321

NetRange:   74.86.0.0 - 74.86.255.255
CIDR:       74.86.0.0/16
OriginAS:   AS36351
NetName:    SOFTLAYER-4-4
NetHandle:  NET-74-86-0-0-1
Parent:     NET-74-0-0-0-0
NetType:    Direct Allocation
NameServer: NS1.SOFTLAYER.COM
NameServer: NS2.SOFTLAYER.COM
Comment:    abuse@softlayer.com
RegDate:    2007-05-16
Updated:    2007-11-14

RAbuseHandle: ABUSE1025-ARIN
RAbuseName:   Abuse
RAbusePhone:  +1-214-442-0605
RAbuseEmail:  abuse@softlayer.com 

RNOCHandle: IPADM258-ARIN
RNOCName:   IP Admin
RNOCPhone:  +1-214-442-0600
RNOCEmail:  ipadmin@softlayer.com 

RTechHandle: IPADM258-ARIN
RTechName:   IP Admin
RTechPhone:  +1-214-442-0600
RTechEmail:  ipadmin@softlayer.com 

OrgAbuseHandle: ABUSE1025-ARIN
OrgAbuseName:   Abuse
OrgAbusePhone:  +1-214-442-0605
OrgAbuseEmail:  abuse@softlayer.com

OrgTechHandle: IPADM258-ARIN
OrgTechName:   IP Admin
OrgTechPhone:  +1-214-442-0600
OrgTechEmail:  ipadmin@softlayer.com

# ARIN WHOIS database, last updated 2009-07-23 20:00
# Enter ? for additional hints on searching ARIN's WHOIS database.

Found a referral to rwhois.softlayer.com:4321.

%rwhois V-1.5:003fff:00 rwhois.softlayer.com (by Network Solutions, Inc. V-1.5.9.5)
network:Class-Name:network
network:ID:NETBLK-SOFTLAYER.74.86.32.0/19
network:Auth-Area:74.86.32.0/19
network:Network-Name:SOFTLAYER-74.86.32.0
network:IP-Network:74.86.48.96/29
network:IP-Network-Block:74.86.48.96-74.86.48.103
network:Organization;I:SoftLayer Technologies, Inc.
network:Street-Address:1950 Stemmons Freeway Suite 2043
network:City:Dallas
network:State:TX
network:Postal-Code:75207
network:Country-Code:US
network:Tech-Contact;I:sysadmins@softlayer.com
network:Abuse-Contact;I:abuse@softlayer.com
network:Admin-Contact;I:IPADM258-ARIN
network:Created:20070708
network:Updated:20071205
network:Updated-By:ipadmin@softlayer.com

%referral rwhois://root.rwhois.net:4321/auth-area=.
%ok

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