How to Find Out the IP Address of a Router

 

Level of difficulty: 

Intermediate

The IP (Internet Protocol) address of a router can be useful if you want to secure your wireless network. It can prevent unauthorized users to gain access to your wireless network. You can also make some changes to your router’s settings by accessing the settings from your Web browser. In order to do this, you need to know the IP address of your router.

Materials Needed:

- Internet connection
- router’s manual (optional)

Step 1

You can easily get the IP address of your router by checking the user’s manual. If you do not have the manual, you can access the Internet and check the router’s website for the IP address.

Step 2

Open a Web browser window. Search for the official website of your router. Search for the model of the router that you are using. Usually, manufacturer’s use a default IP address for each model of a router. Once you have found the model of your router, check the online manual for the IP address.

Step 3

If you cannot find the specific model of your router on the router’s website, try searching for it on search engines. Type the model of your router on the search bar followed by 'default IP address'. This should bring up some results for the IP address of your router.

Step 4

In some cases, the manufacturer does not use the default IP address for the router. Sometimes, the IP address can also be changed manually. You can also get the IP address of your router even if it has been changed. To do this, click on the 'Start' button on the lower left corner of your desktop. Select 'All Programs' from the list. Choose 'Accessories' and choose on 'Command Prompt'.

Step 5

A new window will appear on the screen. On the window, type 'ipconfig' where the cursor is. Press the 'Enter' key on your keyboard.

Step 6

Wait for the results for a few seconds. A lot of information regarding your computer and network will appear on the screen. Search for the line that reads 'Default Gateway'. The numbers beside this line is your router’s IP address.

Step 7

You can change the settings of your router by using the IP address. On your Web browser window, type the IP address on the address bar. This should open a page containing your router’s settings.

-: Packet Header Analysis :-

-: Packet Header Analysis :-

Following are the easy to analyze ICMP, TCP and UDP packet headers along with short description.
All header Drawings by- "Matt Baxter" (www.fatpipe.org/~mjb/Drawings/)

ICMP Message Types :- ICMP message type-code/name format
0 Echo Reply
3 Destination Unreachable
4 Source Quench
5 Redirect
8 Echo
11 Time Exceeded
12 Parameter Problem
13 Timestamp
14 Timestamp Reply
15 Information Request
16 Information Reply

Checksum :- The checksum is the 16-bit ones's complement of the one's complement sum of the ICMP message starting with the ICMP Type.

RFC 792 :- Please refer to RFC 792 for Internet Control Message Protocol (ICMP) Specification.

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TCP Flags :- C E U A P R S F

C 0x80 Reduced (CWR)

E 0x40 ECN Echo (ECE)

U 0x20 Urgent

A 0x10 Ack

P 0x08 Push

R 0x04 Reset

S 0x02 Syn

F 0x01 Fin

TCP Options :-

0 End of Options List

1 No Operation (NOP, Pad)

2 Maximum Segment Size

3 Window Scale

4 Selective ACK ok

8 Timestamp

Checksum :- Checksum of entire TCP segment and pseudo header (parts of IP header)

Offset :- Number of 32-bit words in TCP header, minimum value of 5. Multiply by 4 to get byte count.

RFC 793 :- Please refer to RFC 793 for Transmission Control Protocol (TCP) Specification.

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Source Port :- an optional field, when meaningful, it indicates the port of the sending process, and may be assumed to be the port to which a reply should be addressed in the absence of any other information. If not used, a value of zero is inserted.

Destination Port :- Destination Port has a meaning within the context of a particular internet destination address.

Length :- Length is the length in octets of this user datagram including this header and the data. (This means the minimum value of the length is eight.)

Checksum :- Checksum is the 16-bit one's complement of the one's complement sum of a pseudo header of information from the IP header, the UDP header, and the data, padded with zero octets at the end (if necessary) to make a multiple of two octets.

RFC 768 :- Please refer to RFC 768 for User Datagram Protocol (UDP) Specification.

-: IP Address :-

-: IP Address :-

Definition :-
"An Internet Protocol (IP) address is a numerical identification (logical address) that is assigned to devices participating in a computer network utilizing the Internet Protocol for communication between its nodes".   -- Wikipedia

The Internet Protocol (IP) has two versions currently in use which are IPv4 and IPv6.
This article represents to IPv4 version only.

In general, an IP address is a 32-bit decimal number that is normally written as four numbers between 1 to 255 (8 bits or 1 byte each), each seperated from the other by a decimal point. This standard is known as "Dotted Decimal Notation".
e.g.-   117.200.77.110

IP addresses are divided into number of ranges/classes as given in the table below-

Class	Range
A	0.0.0.0 to 127.255.255.255
B	128.0.0.0 to 191.255.255.255
C	192.0.0.0 to 223.255.255.255
D	224.0.0.0 to 239.255.255.255
E	240.0.0.0 to 255.255.255.255

e.g.-  IP Address 192.168.24.114 belongs to Class 'C'.

How to find out IP Address of your system ?
1) Connect to the Internet.
2) Launch MS-DOS Command Prompt.
3) Type "netstat -n", Press Enter.

You will get the output similar to following-

The IP Address shown in local address field denotes IP Address of your system.
In this case it is 117.200.160.151

IP Address Formats :-
Four different formats of IP Address along with example is as given below-

1) Domain Name System (DNS) : www.insecure.in
2) DWORD Format : 2928008962
3) Octal Format : 0256.0205.0337.002
4) Dotted Decimal Format : 174.133.223.2

Converting DNS IP Address into Normal IP Address :-
You can easily get the IP Address of any domain by various methods such as WHOIS, Netstat, Ping, Traceroute, etc.
Here I have used 'Ping' to get IP Address.

1) Connect to the Internet.
2) Launch MS-DOS Command Prompt.
3) Type "ping domainname", Press Enter.

You will get the output similar to following-

Here, IP Address for Domain "www.insecure.in" is "174.133.223.2"

Thus by typing "http://www.insecure.in" OR "http://2928008962" OR "0256.0205.0337.02" OR "174.133.223.2" in your browser will take you to the same site.

Not all of these formats work in all browsers.