Ephemeral port

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ephemeral Port is a short-lived transport protocol port for Internet Protocol (IP) communications. Ephemeral ports are allocated automatically from the range specified by the IP stack software. The efemeral port is usually used by the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), or the Stream Control Transmission Protocol (SCTP) as the assignment of ports to the client end of the client-server communication to the well-known ports on the server.

On the server, the ephemeral port can also be used as a port assignment on the server end of the communication. This is done to continue communication with clients that were originally connected to one of the famous service ports on the server. The File Transfer Protocol (FTP) and Remote Procedure Call (RPC) protocols are two protocols that can behave like this. Note that the term "server" here includes workstations that run network services that accept connections starting with other clients (eg Remote Desktop Protocol).

Allocations are temporary and only valid for the duration of a communication session. After completion (or timeout) of the communication session, ports are available for reuse. Because ports are used on request, they are also called dynamic ports .

Video Ephemeral port

Range

The Internet Assigned Numbers Authority (IANA) suggests a range of 49152 to 65535 (2 ¹⁵ 2 ¹⁴ to 2 ¹⁶ -1) for dynamic or private ports.

Many Linux kernels use port ranges from 32768 to 61000. FreeBSD has used the IANA port range since the 4.6 release. Previous versions, including Berkeley Software Distribution (BSD), use ports 1024 to 5000 as short ports.

Microsoft Windows operating system via XP uses the range 1025-5000 as an efemeral port by default. Windows Vista, Windows 7, and Server 2008 use the IANA range by default. Windows Server 2003 uses the 1025-5000 range by default, until a Microsoft MS08-037 security update from 2008 is installed, after which it uses the IANA range by default. Windows Server 2008 with Exchange Server 2007 installed has a standard port range of 1025-60000. In addition to the standard ranges, all versions of Windows since Windows 2000 have the option to specify a custom range anywhere in 1025-65535.

Maps Ephemeral port

Configuration characteristics

If a particular server software is used, which uses a non-transparent special port range to initiate some further connections, it is necessary to ensure that this particular port range and the efemeral port range do not overlap.

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Note

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See also

• Internet Protocol Suite
• List of TCP and UDP port numbers

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References

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External links

• Ephemeral Port Range on NcFTP.com
• Selection of Ephemeral Source Ports in Team Cymru

This article is based on material extracted from the Free Online Computing Dictionary before November 1, 2008 and is incorporated in the "subscription" provision of GFDL, version 1.3 or later.

Source of the article : Wikipedia