Telnet
Telnet is the ultimate hacking tool which every hacker must know how to use before he can even think about Hacking into servers. Telnet is better described as a protocol which requires or runs on TCP\IP. It can be used to connect to remote computers and to run command line programs by simply typing commands into it's GUI window. Telnet does not use the resources of the client's computer but uses the resources of the server to which the client has connected. Basically it is a terminal emulation program that allows us to connect to remote computers. It is found at c:\windows\telnet.exe in Win9x systems and c:\winnt\system32\telnet.exe in NT machines. If the Path statement in your machine is set correctly then if you just type Telnet at the DOS prompt then it will bring a GUI Windows which actually is the Telnet program. How do I connect to remote computers using telnet? Well it is really simple to connect to remote computers using telnet.Well first launch the telnet application by typing telnet at the DOS prompt. Once the Telnet windows pops up click on Connect>Remote System then in the host name type the host i.e the remote computer you want to connect to. Then in the Port select the port you want to connect to in this case leave it to Telnet. Almost always leave the TermType to vt100. ***********************
Hacking Tip: You may be wondering what the Term Type stands for. Well actually it represents various kinds of display units. We use vt100 as it is compatible with most monitors. **********************
Then click connect and you will be connected to the remote machine. Now if you are a newbie you would be using the above method of telnetting to a remote computer and you would not be port surfing. Well if you really want to leanr to hack, port surfing is a must as without learning to port surf you will not be able to find out The basic syntax of the telnet command is C:\>telnet
hostname.com Now let's go through this syntax, the word telnet is followed by the host name or the IP address of the host you want to connect to which is then followed by the port on the remote computer you want to connect to.If you are confused by the new terms read on and things will become clearer. What exactly is an IP Address? Like in the real world, everyone has got an individual Home Address or telephone number so that, that particular individual can be contacted on that number or address, similiarly all computers connected to the Internet are given a unique Internet Protocol or IP address which can be used to contact that particular computer. In geek language an IP address would be a decimal notation that divides the 32 bit Internet addresses (IP) into four 8 bit fields. Does the IP address give me some information or do the numbers stand for anything? Let take the example of the following IP address:
202.144.49.110 Now the first part , the numbers before the first decimal i.e 209 is the Network number or the Network Prefix.. This means that it identifies the number of the network in which the host is. The second part i.e. 144 is the Host Number, that is it identifies the number of the host within the Network. This means that in the same Network, the network number is same. In order to provide flexibilty in the size of the Network ,there are different classes of IP addresses: Address Class Dotted Decimal Notation Ranges Class A ( /8 Prefixes) 1.xxx.xxx.xxx through 126.xxx.xxx.xxx Class B ( /16 Prefixes) 128.0.xxx.xxx through 191.255.xxx.xxx Class C ( /24 Prefixes) 192.0.0.xxx through 223.255.255.xxx The various classes will be more clear after reading the next few lines. Each Class A Network Address contains a 8 bit Network Prefix followed by a 24 bit host number.They are considered to be primitive.They are referred to as "/8''s" or just "8's" as they have a 8 bit Network prefix. In a Class B Network Address there is a 16 bit Network Prefix followed by a 16 bit Host number. It is reffered to as "16's". A class C Network address conatins a 24 bit Network Prefix and a 8 bit Host number. It is refered to as "24's" and is commonly used by most ISP's. Due to the growing size of the Internet the Network Administrators faced many problems. The Internet routing tables were beginning to grow and now the administrators had to request another network number from the Internet before a new network could be installed at their site. This is where subnetting caame in. Now if your ISP is a big one and if it provides you with dynamic IP addresses then you will most probably see that whenever you log on to the net, your IP address will have the same first 24 bits and only the last 8 bits will keep changing. This is due to the fact that when subnetting comes in then the IP Addresses structure becomes: xxx.xxx.zzz.yyy where the first 2 parts are Network Prefix numbers and the zzz is the Subnet number and the yyy is the host number. So you are always connected to the same Subnet within the same Network. As a result the first 3 parts will remain same and only the last part i.e. yyy is variable. You may be wondering, what happeded to 127 as after 126.xxx.xxx.xxx there is straightaway 128.0.xxx.xxx. Well
127.0.0.1 is reserved for the loopback function, this means that it refers to the localhost, this means that if you try to telnet to
127.0.0.1 , then the Telnet client will try to connect to your own computer. IP addresses can be of to types Dynamic and Static. Now most of us connect to the Internet by dialing into our ISP through Dial up Networking and using PPP( Point to Point Protocol). Now when you connect to your ISP's server you are assigned a unique IP number which is then used to transfer data to and from your computer. That becomes your address. Now the IP address that you are assigned changes everytime your connect to your ISP i.e. you are assigned a new different IP every time you dial into your ISP, that is how it becomes Dynamic.This means that if you have obtained the IP address of a person once, then if he disconnects and reconnects then you will have to get his IP address again. While other ISP's provide you with a permanent IP address as soon as you register with them. In that case your IP remains the same every time you connect to their server and is thus known as a permanent IP address. *******************
Hacking Tip: You can find out if an IP address is a Dynamic or Static by issuing the ultimate mapping tool on the net: nslookup.Give the following command : nslookup hostname where hostname is substituted by an IP address and if the result is Non-Existant Host/ Domain then the IP is a Dynamic one. If it return the hostname which is human understandable then you can be pretty sure that the IP address is a static one. For more information on DNS lookup and nslookup read on. ******************
Now IP addresses are very difficult to remember, who can memorize IP addresses of all the computers he wants to connect to or the sites he wants to visit.Say for example I am sure you would find
hotmail.com more easier to remember than something like
203.43.54.12. Here comes in DNS or Domain Name Systems.Read on for more info on DNS.
