What is tcp port 1037. Basics of network ports

UDP APPS

The UDP protocol also supports Trivial File Transfer Protocol (TFTP), Simple Network Management Protocol (SNMP), and Routing Information Protocol (RIP) among many other applications.
TFTP (Simple File Transfer Protocol). It is mainly used to copy and install an operating system on a computer from a file server,

TFTP. The TFTP protocol is a smaller application than the File Transfer Protocol (FTP). Typically, TFTP is used on networks for simple file transfers. TFTP includes its own error control and serial numbering mechanism and, therefore, this protocol does not need additional services at the transport layer.

SNMP (Simple Network Management Protocol) monitors and manages networks and devices attached to them, and collects information about network performance. SNMP sends PDU messages that allow network management software to control devices on the network.

RIP (Routing Information Protocol) is an internal routing protocol, which means it is used within an organization but not on the Internet.

TCP APPLICATIONS

The TCP protocol, among many other applications, also supports FTP, Telnet and Simple Mail Transfer Protocol (SMTP).

FTP (File Transfer Protocol) is a full-featured application that is used to copy files by running a client application on one computer that is linked to an FTP server application on another remote computer. With this application, files can be received and sent.

Telnet allows you to establish terminal sessions with a remote device, typically a UNIX host, router, or switch. This gives the network administrator the ability to control the network device as if it were in close proximity, using the computer's serial port for control. The usefulness of Telnet is limited to systems that use the character mode command syntax. Telnet does not support graphical user environment management.

SMTP (Simple Mail Transfer Protocol) is a mail transfer protocol for the Internet. It supports the transfer of email messages between email clients and mail servers.

WELL KNOWN PORTS
Well-known ports are assigned by the IANA and range from 1023 and below. They are assigned to applications that are essential to the Internet.

REGISTERED PORTS
Registered ports are cataloged by IANA and range from 1024 to 49151. These ports are used by licensed applications such as Lotus Mail.

DYNAMIC PORTS
Dynamically assigned ports are assigned numbers from 49152 to 65535. Numbers for these ports are assigned dynamically for the duration of a particular session.

Sources: Wikipedia, Microsoft, portscan.ru

How to find out what ports are open on a computer?

1. For Windows: Start → "cmd" → Run as administrator → "netstat -bn"
2. In an antivirus program such as Avast, it is possible to view active ports in the Firewall: Tools -> Firewall -> Network Connections.

Also useful netstat commands:

To display both the Ethernet statistics and the statistics for all protocols, type the following command:

netstat -e -s

To display the statistics for only the TCP and UDP protocols, type the following command:

netstat -s -p tcp udp

To display active TCP connections and the process IDs every 5 seconds, type the following command:

nbtstat -o 5

To display active TCP connections and the process IDs using numerical form, type the following command:

nbtstat -n -o

For TCP sockets, the following status values ​​are valid:

List of most commonly used ports

There are two types of computer-to-computer data exchange - data thunders and sessions. datagram- this is a message that does not require an acknowledgment of receipt from the receiving party, and if such an acknowledgment is necessary, then the addressee must send a special message himself. To exchange data in this way, the receiving and transmitting parties must strictly adhere to a certain protocol in order to avoid information loss. Each datagram is an independent message, and if there are several datagrams on the LAN, their delivery to the addressee, generally speaking, is not guaranteed. However, a datagram is usually part of a message, and on most LANs, datagrams are much faster than messages in sessions.

AT session a logical link is supposed to be created for the exchange of messages between computers and the receipt of messages is guaranteed. While datagrams can be transmitted at arbitrary times, the session must be closed before the message is sent, and the session must be closed when the data exchange is completed.

The operating systems of most computers support multi-program mode, i.e. multiple programs are running at the same time (multiple processes are running in parallel). With some degree of accuracy, we can say that the process is the final destination for the message. However, because processes are created and terminated dynamically, the sender rarely has sufficient information to identify a process on another computer. Therefore, it becomes necessary to determine the destination of data based on the functions performed by the processes, without knowing anything about the processes that are implemented by these functions.

In practice, instead of considering a process as an end destination, each computer is considered to have a set of some destinations called protocol ports. Each port is identified by a positive integer (from 0 to 65535). In this case, the operating system provides a communication mechanism that processes use to specify the port they are running on or the port they want to access. Normally, ports are Buffered, and data arriving at a particular port before a process is ready to receive it will not be lost: it will be queued until the process retrieves it.

To better understand the technology of ports, imagine that you have come to the bank to make a deposit. To do this, you need to go to a certain window where the operator will draw up the documents and you will open an account. In this example, the bank is a computer, and the bank operators are programs that perform certain work, but the windows are the ports, while each window in the bank is often numbered (1, 2,3 ...).

The same applies to ports, so in order to bind to a port on another computer, the sender must know both the IP address of the destination computer and the port number on the computer. Each message contains both the port number of the computer to which the message is addressed and the port number of the source computer to which the response is to be received. Thus, the ability to respond to the sender for each process is implemented.

TCP/IP ports 0 to 1023 are privileged and are used by network services, which in turn run with administrator (superuser) privileges. For example, the Windows File and Folder Service uses port 139, but if it is not running on the computer, then an attempt to access this service (that is, this port) will receive an error message.

TCP/IP ports 1023 to 65535 are unprivileged and are used by client programs to receive responses from servers. For example, a user's web browser accessing a web server uses port 44587 on their computer, but accesses port 80 of the web server. Upon receiving the request, the web server sends a response to port 44587, which is used by the web browser.

Hello everyone, today I will tell you how the TCP protocol differs from UDP. The transport layer protocols following IP in the hierarchy are used to transfer data between application processes implemented in network nodes. A data packet received from one computer to another via the Internet must be transferred to the handler process, and precisely for a specific purpose. The transport layer takes responsibility for this. At this level, the two main protocols are TCP and UDP.

What do TCP and UDP mean

TCP– a transport protocol for data transmission in TCP/IP networks, which preliminarily establishes a connection to the network.

UDP– a transport protocol that transmits datagram messages without the need to establish a connection in an IP network.

I remind you that both protocols work at the transport layer of the OSI or TCP / IP model, and understanding how they differ is very important.

Difference between TCP and UDP protocols

The difference between TCP and UDP protocols is the so-called “delivery guarantee”. TCP requires a response from the client to which the data packet is delivered, an acknowledgment of delivery, and for this it needs a pre-established connection. Also, the TCP protocol is considered reliable, while UDP has even received the name “unreliable datagram protocol. TCP eliminates data loss, duplication and mixing of packets, delays. UDP allows all this, and it does not require a connection to work. Processes to which data is sent over UDP must make do with what they receive, even with losses. TCP controls the congestion of the connection, UDP controls nothing but the integrity of received datagrams.

On the other hand, due to such non-selectivity and lack of control, UDP delivers data packets (datagrams) much faster, therefore, for applications that are designed for high bandwidth and fast exchange, UDP can be considered the optimal protocol. These include network and browser games, as well as streaming video viewers and applications for video communication (or voice): from the loss of a packet, complete or partial, nothing changes, it is not necessary to repeat the request, but the download is much faster. The TCP protocol, being more reliable, is successfully used even in mail programs, allowing you to control not only traffic, but also the length of the message and the speed of traffic exchange.

Let's look at the main differences between tcp and udp.

1. TCP guarantees the delivery of data packets in unchanged form, sequence and without loss, UDP guarantees nothing.
2. TCP enumerates packets during transmission, but UDP does not.
3. TCP operates in duplex mode, in one packet you can send information and confirm receipt of the previous packet.
4. TCP requires a pre-established connection, UDP does not require a connection, it is just a data stream.
5. UDP provides higher data transfer rates.
6. TCP is more reliable and controls the communication process.
7. UDP is preferable for programs that play streaming video, videophony and telephony, network games.
8. UPD does not contain data recovery features

Examples of UDP applications, for example, are transferring DNS zones to Active Directory, where reliability is not required. Very often they like to ask such questions at interviews, so it is very important to know the differences between tcp and udp.

TCP and UDP headers

Let's look at how the headers of the two transport protocols look like, since here the differences are cardinal.

UDP header

• 16 bit source port > Specifying the source port for UDP is optional. If this field is used, the recipient may send a response to this port.
• 16 bit destination port > Destination port number
• 16 bit UDP length > Message length including header and data.
• 16 bit checksum > Header and data checksum to check

TCP header

• 16 bit source port > Source port number
• 16 bit destination port > Destination port number
• 32 bit sequence number > The sequence number is generated by the source and used by the destination to reorder packets to create the original message and send an acknowledgment to the source.
• 32 bit acknowledgment number > If the ACK bit of the Control field is set, this field contains the next expected sequence number.
• 4 bits header length > Information about the beginning of the data packet.
• reserve > Reserved for future use.
• 16 bit checksum > Header and data checksum; it determines if the packet has been corrupted.
• 16 bit urgent pointer > In this field, the target device receives information about the urgent nature of the data.
• Parameters > Optional values ​​that are specified if necessary.

The window size allows you to save traffic, consider when its value is 1, then for each sent response, the sender waits for confirmation, which is not entirely rational.

With a window size of 3, the sender already sends 3 frames, and waits for 4, which implies that he has all three frames, +1.

I hope you now have an idea about the differences between tcp udp protocols.