Well-known portsidentify servers that carry standard services such as the File Transfer Protocol (FTP) or Telnet. The same service is always allocated the same port number, so, for example, FTP is always 21 and Telnet always 23. Networks generally reserve port numbers 1 through 255 for well-...
The port numbers of FTP processes are belowA. 20 B. 21 C. 22 D. 23 如何将EXCEL生成题库手机刷题 手机使用 分享 复制链接 新浪微博 分享QQ 微信扫一扫 微信内点击右上角“…”即可分享 反馈 收藏 举报参考答案: A B 复制 纠错 举一反三 根据NB/T20115要求规定,使用螺栓拉伸机完成主螺栓的...
215 NAME system type. Where NAME is an official system name from the list in the Assigned Numbers document. NAME系统类型。 220 Service ready for new user. 新连接的用户的服务已就绪 221 Service closing control connection. 控制连接关闭 225 Data connection open; no transfer in progress. 数据连接...
Well-known port numbers are port numbers forTransmission Control Protocol (TCP)orUser Datagram Protocol (UDP)that have been assigned to specific TCP/IP applications or services by theInternet Assigned Numbers Authority (IANA). Well-known port numbers are assigned within the range 0 through 1023 and...
例如,对于每个TCP/IP实现来说,FTP服务器的TCP端口号都是21,每个Telnet服务器的TCP端口号都是23,每个TFTP(简单文件传送协议)服务器的UDP端口号都是69。任何TCP/IP实现所提供的服务都用知名的1~1023之间的端口号。这些知名端口号由Internet号分配机构(InternetAssignedNumbersAuthority,IANA)来管理。
Well-known ports (0-1023): These ports are also known as system ports, which are assigned to specific services by IANA (Internet Assigned Numbers Authority). Registered ports (1023-49151): These ports are known as user ports and are available for registration IANA. The reason behind registrati...
Can you use the default FTP port numbers for SFTP? The default port number for standard FTP is 21. While it’s technically possible to use port 21 for your SFTP service, it’s not recommended. If you review our discussion about picking alternative ports for your SFTP service above, you ...
Port numbers are defined by convention. HTTP servers generally listen on port 80, ssh servers listen on 22. But there are no requirements that they do. Share Improve this answer Follow answered Sep 30, 2011 at 18:09 P.T. 25.1k77 gold badges6868 silver badges9898 bronze badges Add a...
int getservbyname ( string $service , string $protocol ) getservbyname() returns the Internet port which corresponds to service for the specified protocol as per /etc/services. 参数 service The Internet service name, as a string. protocol protocol is either "tcp" or "udp" (in lowercase)...
例如,对于每个TCP/IP实现来说,FTP服务器的TCP端口号都是21,每个Telnet服务器的TCP端口号都是23,每个TFTP(简单文件传送协议)服务器的UDP端口号都是69。任何TCP/IP实现所提供的服务都用知名的1~1023之间的端口号。这些知名端口号由Internet号分配机构(InternetAssignedNumbersAuthority,IANA)来管理。