Ports and protocols

PORTSAND

PROTOCOLS

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PORTS AND PROTOCOLS

What is a Port?

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In computer hardware, a 'port' serves as an interface between the computer and other computers or peripheral devices.

Physically, a port is a specialized outlet on a piece of equipment to which a plug or cable connects. Electronically, the several conductors making up the outlet provide a signal transfer between devices.

The term 'port' is derived from a latin word 'porta' (gate, entrance, door).

PORTS AND PROTOCOLS

Hardware Ports

a port serves as an interface between the computer and other computers or peripheral devices. In computer terms, a port generally refers to the female part of connection. Computer ports have many uses, to connect a monitor, webcam, speakers, or other peripheral devices. On the physical layer, a computer port is a specialized outlet on a piece of equipment to which a plug or cable connects.

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Typers of portsHardware portsSoftware ports

PORTS AND PROTOCOLS

Software ports

A software port (usually just called a 'port') is a virtual/logical data connection that can be used by programs to exchange data directly.

The most common of these are TCP and UDP ports, which are used to exchange data between computers on the Internet.

TCP :-

TCP is a connection-oriented protocol; it creates a virtual connection between two TCPs to send data. In addition, TCP uses flow and error control mechanisms at the transport level.

UDP :-

The User Datagram Protocol (UDP) is called a connectionless, unreliable transport protocol. It does not add anything to the services of IP except to provide process-to-process communication instead of host-to-host communication.

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PORTS AND PROTOCOLS

1-File Transfer Protocol (FTP)

• Port number (20-21)

• FTP stands for File Transfer Protocol

• Protocol for transferring files over a network. It supports both anonymous and password-mediated access.

• FTP is one of the most commonly used file transfer protocols on the Internet and within private networks. An FTP server can easily be set up with little networking knowledge and provides the ability to easily relocate files from one system to another. FTP control is handled on TCP port 21 and its data transfer can use TCP port 20 as well as dynamic ports depending on the specific configuration.

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PORTS AND PROTOCOLS

2- Secure Shell (SSH)

• Port number (22)

• SSH stands for Secure Shell

• Its an encrypted remote access tool. It supports file transfers and encrypting other protocols.

• SSH is the primary method used to manage network devices securely at the command level. It is typically used as a secure alternative to Telnet which does not support secure connections.

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PORTS AND PROTOCOLS

3-Telnet


• It’s seldom used today, although its client program, telnet, can be a useful network diagnostic tool.

• Telnet is the primary method used to manage network devices at the command level. Unlike SSH which provides a secure connection, Telnet does not, it simply provides a basic unsecured connection. Many lower level network devices support Telnet and not SSH as it required some additional processing. Caution should be used when connecting to a device using Telnet over a public network as the login credentials will be transmitted in the clear.

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PORTS AND PROTOCOLS

4-Simple Mail Transfer Protocol (SMTP)


• SMTP stands for Simple Mail Transfer Protocol

• Main protocol for moving email on the Internet. The sender initiates SMTP transfers

• SMTP is used for two primary functions, it is used to transfer mail (email) from source to destination between mail servers and it is used by end users to send email to a mail system.

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PORTS AND PROTOCOLS

5-Domain Name System (DNS)


• DNS stands for Domain Name Service

• enables computers to look up an IP address by providing a hostname, or vice-versa.

• The DNS is used widely on the public internet and on private networks to translate domain names into IP addresses, typically for network routing. DNS is hieratical with main root servers that contain databases that list the managers of high level Top Level Domains (TLD) (such as .com). These different TLD managers then contain information for the second level domains that are typically used by individual users (for example, cisco.com). A DNS server can also be set up within a private network to private naming services between the hosts of the internal network without being part of the global system.

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PORTS AND PROTOCOLS

6-Dynamic Host Configuration Protocol (DHCP)

• Port number (67/68)

• DHCP stands for Dynamic Host Configuration Protocol

• DHCP is used on networks that do not use static IP address assignment (almost all of them). A DHCP server can be set up by an administrator or engineer with a poll of addresses that are available for assignment. When a client device is turned on it can request an IP address from the local DHCP server, if there is an available address in the pool it can be assigned to the device. This assignment is not permanent and expires at a configurable interval; if an address renewal is not requested and the lease expires the address will be put back into the poll for assignment.

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PORTS AND PROTOCOLS

7-Trivial File Transfer Protocol (TFTP)


• TFTP offers a method of file transfer without the session establishment requirements that FTP uses. Because TFTP uses UDP instead of TCP it has no way of ensuring the file has been properly transferred, the end device must be able to check the file to ensure proper transfer. TFTP is typically used by devices to upgrade software and firmware; this includes Cisco and other network vendors’ equipment.

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PORTS AND PROTOCOLS

8-Finger


• Finger servers provide information about the users of their computers by opening and listening for incoming TCP connections on port 79. This information typically included the user's full name, address, telephone number, title, job name, office location, telephone extension, and so on.

9-Hypertext Transfer Protocol (HTTP)

• Port number(80)

• HTTP is one of the most commonly used protocols on most networks. HTTP is the main protocol that is used by web browsers and is thus used by any client that uses files located on these servers.

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PORTS AND PROTOCOLS

10-Post Office Protocol (POP) version 2-3

• Port number (109–110)

• POP stands for Post Office Protocol

• It enables a recipient to initiate an email transfer, it’s often used as the last leg in email delivery, from a server to the recipient.

• POP version 3 is one of the two main protocols used to retrieve mail from a server. POP was designed to be very simple by allowing a client to retrieve the complete contents of a server mailbox and then deleting the contents from the server.

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PORTS AND PROTOCOLS

11-Structured Query Language(SQL)• Port number (118)

• SQL stands for Structured Query Language

• Its a network-enabled database interface language. If you run an SQL server on your network, client computers can access and modify that database.

12-Network Time Protocol (NTP)

• Port number(123)

• One of the most overlooked protocols is NTP. NTP is used to synchronize the devices on the Internet. Even most modern operating systems support NTP as a basis for keeping an accurate clock. The use of NTP is vital on networking systems as it provides an ability to easily interrelate troubles from one device to another as the clocks are precisely accurate.

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PORTS AND PROTOCOLS

13-DCOM-SCM• Port number(135)

• DCOM Service Control Manager

• The SCM server running on the user's computer opens port 135 and listens for incoming requests from clients wishing to locate the ports where DCOM services can be found on that machine

14-NetBIOS

• Port number(137/138/139)

• NetBIOS itself is not a protocol but is typically used in combination with IP with the NetBIOS over TCP/IP (NBT) protocol. NBT has long been the central protocol used to interconnect Microsoft Windows machines.

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PORTS AND PROTOCOLS

15-Internet Message Access Protocol (IMAP)


• IMAP stands for Internet Message Access Protocol

• Its another recipient-initiated email transfer protocol, similar to POP. IMAP makes it easier for recipients to permanently store and manage email on the server computer, though.

• IMAP version3 is the second of the main protocols used to retrieve mail from a server. While POP has wider support, IMAP supports a wider array of remote mailbox operations which can be helpful to users.

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PORTS AND PROTOCOLS

16-Simple Network Management Protocol (SNMP)


• SNMP is used by network administrators as a method of network management. SNMP has a number of different abilities including the ability to monitor, configure and control network devices. SNMP traps can also be configured on network devices to notify a central server when specific actions are occurring. Typically, these are configured to be used when an alerting condition is happening. In this situation, the device will send a trap to network management stating that an event has occurred and that the device should be looked at further for a source to the event.

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PORTS AND PROTOCOLS

17-Border Gateway Protocol (BGP)


• BGP version 4 is widely used on the public internet and by Internet Service Providers (ISP) to maintain very large routing tables and traffic processing. BGP is one of the few protocols that have been designed to deal with the astronomically large routing tables that must exist on the public Internet

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PORTS AND PROTOCOLS

18-Lightweight Directory Access Protocol (LDAP)


• LDAP stands for Lightweight Directory Access Protocol

• A network protocol for accessing directories, which in this context are a type of database.

• LDAP provides a mechanism of accessing and maintaining distributed directory information. LDAP is based on the ITU-T X.500 standard but has been simplified and altered to work over TCP/IP networks.

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PORTS AND PROTOCOLS

19-Hypertext Transfer Protocol over SSL/TLS (HTTPS)


• HTTPS is used in conjunction with HTTP to provide the same services but doing it using a secure connection which is provided by either SSL or TLS.

20-Lightweight Directory Access Protocol over TLS/SSL (LDAPS)


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PORTS AND PROTOCOLS

• Just like HTTPS, LDAPS provides the same function as LDAP but over a secure connection which is provided by either SSL or TLS

21-Simple Network Paging Protocol (SNPP)


• Simple Network Paging Protocol (SNPP) is a protocol that defines a method by which a pager can receive a message over the Internet. It is supported by most major paging providers, and serves as an alternative to the paging modems used by many telecommunications services.

22-Routing Information Protocol• Port number (520)

• The Routing Information Protocol (RIP) is one of the oldest distance-vector routingprotocols which employ the hop count as a routing metric. RIP prevents routing loops

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PORTS AND PROTOCOLS

by implementing a limit on the number of hops allowed in a path from source to destination.

23-Dynamic Host Configuration Protocol (DHCP)


• Dynamic Host Configuration Protocol (DHCP) is a network protocol that enables a server to automatically assign an IP address to a computer from a defined range of numbers (i.e., a scope) configured for a given network

24-MS-SQL-S• Port number (1433)

• Microsoft-SQL-Server

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PORTS AND PROTOCOLS

• Microsoft's SQL Server, including the desktop editions that are often silently installed with other Microsoft applications, opens and services queries delivered over incoming TCP connections through this port.

25-MS-SQL-M• Port number (1434)

• Microsoft-SQL-Monitor

• Microsoft's SQL Server, including the desktop editions that are often silently installed with other Microsoft applications, opens and services queries delivered over incoming UDP connections through this port.

26- Simple Service Discovery Protocol (SSDP)


• UPnP Simple Service Discovery Protocol

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PORTS AND PROTOCOLS

• This UDP port is opened and used by Universal Plug N' Play (UPnP) devices to receive broadcasted messages from other UPnP devices. UPnP devices broadcast subnet-wide messages to simultaneously reach all other UPnP devices.

27-Network File System


• NFS stands form Network File System

• A protocol, and a server of the same name, for file sharing between Unix and Unix-like OSs

28-MySQL• Port number (3306)

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PORTS AND PROTOCOLS

Used as a database. MySQL is a database system used on

the web.

MySQL is a database system that runs on a server

28-Remote Desktop Protocol(RDP)


• Remote Desktop Protocol (RDP) is a proprietary protocol developed by Microsoft, which provides a user with a graphical interface to connect to another computer over a network connection. The user employs RDP client software for this purpose, while the other computer must run RDP server software

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PORTS AND PROTOCOLS

29-Virtual Network Computing


• This port (and port 5800) are opened by the VNC system allowing remote multi-platform console access.

30-WHOIS


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PORTS AND PROTOCOLS

• WHOIS is a query and response protocol that is widely used for querying databases that store the registered users or assignees of an Internet resource, such as a domain name, an IP address block, or an autonomous system, but is also used for a wider range of other information.

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Ports and protocols