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IP - Internet Protocol

This post is from my official Blog, please leave the source to it : at

I) TCI/IP Model :

First of all, let's talk a little bit about TCP/IP model .
When we talk to each other, we use the same language so everyone can understand .
If computer A wants to send file to computer B, both of them need to use the same language called "Protocol" .

TCP /IP is the most popular stack of Protocols our computers use nowaday to communicate .
TCP/ IP actually is a set of many protocols (for example when computer wants to send e-mail, it uses a protocol named SMTP, when it sends file - it uses FTP ....), its name is represented by 2 protocols : TCP & IP . So hence the name TCP/IP .

II) IP Address :
1) Introduction to IP Address :

- Every computer has to have at least 1 IP address to communicate with others . Just like my house has a address so some girls can send me some gifts .
- When we talk about IP address, we often talk about IP v4 (v = Version) : It comprises 32 bits (1 & 0) , and divides to 4 portions (called Octet ) separated by 3 dots (.) :
For example : 10000000.11000000.10000001.00000001
- It's kind of hard to remember so people write it in decimal number :
(* You need to know how to convert from Binary to Decimal Number - just search on Google)

- IP addresses also have 2 parts : Host ID and Net ID , just like your house's address has Street number and House number .

2) IP address class :

- Classes help us to determine how many bits net id (or host id) owned , notice : bits net id + bits host id = 32 (please take a look at the figure above) .

- Five classes :
Class A : Net ID owns 8 bits, Host ID owns 24 bits .
Class B : ------------- 16 -------------------16 .
Class C : ------------- 24 -------------------8 .
Class D & E : are used for research & multicast .
- So how to know which class this IP address belongs to ?
- Focus on first octet, for example IP address is X.Y.Z.T
X from 1 -> 126 : This IP belongs to class A
X from 128 -> 191 : This IP belongs to class B
X from 192 -> 223 : This IP belongs to class C
X from 224 -> 239 : This IP belongs to class D
X from 240 -> 255 : This IP belongs to class E
X = 127 is used for other purposes . For example : is called loopback address .

3) Public & Private IP address :

a) Public IP address :
- In WAN (Internet)
- Is provided by Service Provider
- Unique in Internet

b) Private IP address :
- In LAN (Local Area Network)
- Is provided by Administrator .
Nice detailed information with good examples.
What is proxy IP address and how can i find it.
A proxy address is an IP address which your computer may use for various services. These include caching (storing local copies to speed up access, security/antivirus, tracking/controlling access - and so on.
If you don't know you need one then you probably don't (assuming you can browse and email OK).

They can, however, be used in a more 'furtive' way to either hide tracks or fool a host into giving you something that may be restricted normally for your IP. Anyone wanting to use the BBC IPLAYER, for example, but with a foreign connection, would need a proxy address registered in the UK in order to be able to play-back.
hmm nice information thanks for providing
Thanks for your providing
Thanks for sharing (I'm studying this domain and it is really fun interesting).
You can make ping in the Command lines of windows to see if you can talk to another ip address.

For example : ping
it will tell you if you can communicate with the other computer.

When ipV6 comes it will get quite a bit more difficult to enter those addresses.

Did you know that IPv6 is coming just because we will miss IPv4 addresses in the short-term period ?
(and there is 14 billion addresses possible...)
The ping command is useful but unfortunately it is likely to be blocked by your own router or other routers on the net....
Ya some servers don't like IGMP but if the data packet is small enough most don't mind it. Google for example you can use as a reliable server to get ping times from.

Useful network related command prompt stuff I use all the time...

netstat -a
I think a lot of modern broadband routers/modems come preconfigured to bounce ping packets....
Coming in you mean? That would make sense. But I definitely can send them out the multiple places still and I have a fairly new router. I know there are some ancient DoS methods using altered ping packets but they can't be doable anymore surely.

Also you can use sites like to do pings and traceroutes
Yes, incoming - just something to be aware of if you try to ping your own system remotely, or a friends system locally....
Ahhhh yes I noticed this actually. Tried to use that to determine whether my machine was on. Switched to an fopen with PHP.
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