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The Ident Protocol (Identification Protocol, IDENT), specified in RFC 1413, is an Internet protocol that helps identify the user of a particular TCP connection. One popular daemon program for providing the ident service is identd. ==Function== The Ident Protocol is designed to work as a server daemon, on a user's computer, where it receives requests to a specified TCP port, generally 113. In the query, a client specifies a pair of TCP ports (a local and a remote port), encoded as ASCII decimals and separated by a comma (,). The server then sends a response that identifies the username of the user who runs the program that uses the specified pair of TCP ports, or specifies an error. Suppose host A wants to know the username of the user who is connecting to its TCP port 23 (Telnet) from the server's (host B) port 6191. Host A would then open a connection to the ident service on host B, and issue the following query: 6191, 23 As TCP connections generally use one unique local port (6191 in this case), host B can unambiguously identify the program that has initiated the specified connection to host A's port 23, should it exist. Host B would then issue a response, identifying the user ("stjohns" in this example) who owns the program that initiated this connection and the name of its local operating system: 6193, 23 : USERID : UNIX : stjohns But if it would turn out that no such connection exists on host B, it would instead issue an error response: 6195, 23 : ERROR : NO-USER All ident messages should be delimited by an end of line sequence consisting of the carriage return and linefeed characters (CR+LF). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ident protocol」の詳細全文を読む スポンサード リンク
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