常见的服务及端口概览

远程连接

Service	Port	Transport Protocol
Telnet	23（明文传输，极不安全）	TCP/UDP
SSH	22	TCP/UDP/SCTP
Windows Remote Desktop	3389	TCP

文件传输

Service	Port	Transport Protocol
TFTP	69	UDP
FTP	21	TCP/UDP/SCTP
SFTP	115	TCP/UDP

E-mali

Service	Port	Port for SSL	Transport Protocol
IMAP	143