Port Number 각 서비스의 포트번호에 대해 알아보겠다. (이 외에도 있으니 참조) 20, 21(TCP) : FTP(데이터전송/제어) 22(TCP) : SSH(Secure Shell) 23(TCP) : Telnet 25(TCP) : SMTP 메일 전송 (Simple Mail Transfer Protocol) 42(TCP) : Name Server(Host Name Server) 53(TCP/UDP) : DNS 67(UDP) : DHCP 69(UDP) : TFTP (Trivial File Transfer (인증없는 파일전송)) 70(TCP) : Gopher 79(TCP) : Finger 80(TCP) : HTTP (웹서비스) 88(UDP) : Kerberos 101(TCP) : Host Name (NIC Host Name Server) 107(TCP) : rTelnet (Remote Telnet Service) 109(TCP) : POP2 110(TCP) : POP3 119(TCP) : NNTP 123(TCP) : NTP 135(TCP) : RPC 143(TCP) : IMAP 161(UDP) : SNMP 162(UDP) : SNMP-TRAP 194(TCP) : IRC (Internet Relay Chat Protocol) 213(UDP) : IPX 389(TCP) : IDAP 443(TCP) : HTTPS (HTTP protocol over TLS/SSL) 500(UDP) : IPsecISKMP 515(TCP) : LPD(Printer) 593(TCP) : RPC over HTTPS 636(TCP) : LDAPS 989(TCP) : FTPS (FTP Protocol, Data, over TLS/SSL) 990(TCP) : FTPS (FTP Protocol, Control, over TLS/SSL) 993(TCP) : IMAPS (IMAP4 Protocol over TLS/SSL) 995(TCP) : POP3S (POP3 Protocol over T...