Telnet,ssh1,ssh2,telnet/ssl,rlogin,serial,tapi,raw

First,Telnet

UsingTelnetto access the remote computer'sTCP/IPprotocol to control your network devices,The equivalent of shouting your username and password when you leave a building. Someone will listen very quickly, and they will take advantage of your lack of security awareness. Traditional network service programs such as:FTP,Popand thetelnetAre inherently unsafe, because they transmit passwords and data in plaintext on the network, and those who are practical are very easy to intercept these passwords and data. Also, there are weaknesses in the way these service programs are validated. is very easy to be"Middleman"(Man-in-the-middle) attack in such a way. So-called"Middleman"way of attacking, is"Middleman"impersonate a real server to receive your data to the server, and then impersonate you to pass the data to the real server. The data transfer between the server and you is"Middleman"after the hands and feet. There will be a very serious problem.

The Telnet protocol is a member of the TCP/IP protocol family and is the Standard protocol and main way of Internet remote login service. It provides the user with the ability to complete the remote host on the local computer. Use the Telnet program on the end user's computer . Use it to connect to the server. End users can enter commands in the telnet program, which are executed on the server. Just like typing directly on the console of the server.

You can control the server locally.

To start a telnet session. You must enter username and password to log on to the server. Telnet is a frequently used method of remote control of Webserver .

　Telnet The telnet Service is divided into the following 4 a process:

　　1 ) to establish a connection to the remote host locally.

The process is actually to establish a TCP Connection, the user must know the remote host Ip address or domain name;

　　2 ) The username and passwords entered on the local terminal and whatever commands or characters are entered later NVT ( Net Virtual Terminal ) format to the remote host.

The process is actually sending an IP packet from the local host to the remote host .

　　3 ) to output the remote host NVT formatted data into a locally accepted format and sent back to the local terminal. Contains input command echo and command run results;

　　4 Finally, the local terminal makes an undo connection to the remote host. The procedure is to revoke a TCP connection.

Second,SSH

SSH is the abbreviation for Secure Shell , which is provided by The Network Working Group of theIETFworking Group SSH is a security protocol based on the application layer and the transport layer. SSH is now a more reliable protocol that provides security for Telnet sessions and other network services.

The use of SSH protocol can effectively prevent the information leakage in the remote management process. SSH is an industry standard for replacing Telnet and other remote console management applications.

SSHcommands are encrypted and classified in several ways. SSHhas a very versatile, it can replacetelnet, but also be able toFTP,Pop, evenPPPto provide a safe"Channel". SSH (Secure SHell)There are two incompatible version numbers so far.--ssh1and theSSH2.

    ssh1 1.3 1.5 two version number. ssh1 adopted des 3des , blowfish RC4 rsa

SSH1 Use cyclic redundancy check codes ( CRC ) To ensure the integrity of the data, but later found that the method is flawed.

SSH2avoids theRSAthe patent problem, and patched up theCRCthe defect. SSH2using the digital Signature Algorithm (DSA) andDiffie-hellman(DH) algorithm to replaceRSAto complete the exchange of the symmetric key, verify the code with the message (HMAC) to replaceCRC. At the same timeSSH2added aAESand theTwofishequal symmetric encryption algorithm.

Third,Telnet/ssl

Secure Socket Layer, forNetscapedeveloped to protect theInternetSecurity of data transmitted on the data, using the encryption(encryption)technology to ensure that data is not intercepted and tapped during transmission over the network. The general General specification is+ bitsafety standards, the United States has launched- bitHigher safety standards, but limit exit. Just to3.0The version number abovei.e.orNetscapebrowsers can supportSSL.

The current version number is 3.0. It has been widely used to Authenticate and encrypt the transmission of data between WEB browsers and servers.

The SSL protocol is located between the TCP/IP protocol and various application layer protocols, providing security support for data communication.

SSL The agreement can be divided into two tiers: SSL Recording Protocol ( SSL Record Protocol ): It is built on a reliable transport protocol (e.g. TCP ) above. Provides support for the basic functions of data encapsulation, compression and encryption for high-level protocols.

SSL Handshake Protocol ( SSL Handshake Protocol ): It builds on SSL on the record protocol, it is used to authenticate the two parties, negotiate the encryption algorithm, and exchange the encryption key before the actual transmission data is started.

the services provided by the SSL protocol are mainly:

1) authenticate users and servers to ensure that the data is sent to the correct client and server.

2) Encrypt data to prevent the data from being stolen in the middle;

3) Maintain the integrity of the data and ensure that the data is not changed during transmission.

SSL (Secure Sockets layer ), and its successor Transport Layer Security (Transportlayer safety, TLS ) is a security protocol that provides security and data integrity for network communications , is certificate-based authentication.

Telnet/ssl is a Telnet with SSL .

Iv.Rlogin

Rlogin originated from Berkeley Unixand started it to work only between UNIX systems. It is now possible to execute on other operating systems. the Rlogin and Telnet functions are similar in use, but are much simpler.

Telnet,ssh1,ssh2,telnet/ssl,rlogin,serial,tapi,raw

Today, new telnet options are added to telnet , which makes it possible to add a lot of code to the Telnet implementation. and Rlogin still change little, or relatively simple.

Wu,Serial

Serial refers to one event at a time, which is usually the opposite of multiple events occurring in parallel.

In the transmission of data, it is often used to time division and air separation technology. The transmission of a single bit in a serial send message is separated by time, and the space (over multiple lines or paths) is separated in the case of multiple bits being sent in parallel.

In computer hardware and transmitting data: Serial connections, operations, and media often mean slower and simpler operations, while parallelism means faster operations.　　    Such hints are not always correct, as the serial media (for example, fiber-optic cables) can be much faster than a medium that transmits multiple signals in parallel. In a PC , a printer is usually connected by a parallel interface and a cable. So that you can print faster.

The keyboard and mouse require only serial interfaces and lines.

Traditional computers and their programs often work serially. The computer reads the program and runs its instructions one after the other, however, some modern computers have multiple processors. Commands can be run in parallel.

Vi.TAPI

TAPI is the abbreviation for the Telephony Application Programming Interface (telephone application programming Interface). It enables users to talk to people on their computers by phone or video phone with a person on one end of the phone.

Developers use TAPI - written applications to effectively leverage the services of telephony providers, access them through a simulated Modem , and access Professional user switches ( PBX) provides advanced functionality.

TAPIis installed on your computer, and you have theright applications and hardware installed, so you can:

1. be able to see the person you are talking to

2. Click on someone's photo to make the call

3. be able to add a voice file to the e-mail you send. You can also listen to the voice files in the e-mail you receive .

4. use a similar graphical user interface (GUI) to set up a conference call and then participate in the meeting on time.

5. Sending and receiving faxes

6. be able to tap the code to control the computer's own initiative to answer a number of calls

7. Portable Wireless phone

Seven,RAW

RAWthe protocol is the default protocol for most print devices. In order to sendRAWPrint server will open a network interface for the printerTCPflow. For many devices. This interface will be the port9100. When you createTCP/IPafter Port,Windowswill followRFC 1759(Printer MIB), usingSNMPto query the device's object identifier (Object Identifier. OID).

Assuming the device returns a value, parse the system file Tcpmon.ini to find a match.

Assume that the printer manufacturer provides special configuration information for a specific device. These configuration information is created together with the configuration settings.

For example, some external print server interfaces support more than one printer (e.g.. Hewlett Packard JetDirect EX) with 3 parallel port connections . A manufacturer can use a different port to indicate which printer a job should be submitted to (for example, submit the job 9102 to Port1and the job 9103 Submit to Port 2 and so on). This feature is useful for print server interfaces that require the use of a special port name, such as PASS port on some IBM network printers .

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Telnet,ssh1,ssh2,telnet/ssl,rlogin,serial,tapi,raw