There’s the ports everyone knows, like telnet and ftp but being out of the networking for a while i’ve forgotten some and I learned others
This was a good refreasher for me and I came away with some of the ports i hadn’t known.
Telnet tcp/23 Nonencrypted, in the clear SSH tcp/22 Encrypted Looks and feel of telnet DNS udp/53 Domain name to ipaddress SMTP Simple Mail Transfer Protocol tcp/25 Email server Used for outgoing mail SFTP tcp/22 secure File transfer protocol Uses SSH, that's why same port Can resume interrupted transfers Has remote file removal Has directory listing FTP tcp/20 (active mode data) tcp/21(control) Transfers files Has username/password List, add, delete.. Tftp udp/69 trivial file transfer protocal No login Reads and writes DHCP udp/67, udp/68 Dynamic Host Configuration Protocol Required DHCP server Pool of ip addresses Has lease time and must renew ip at set intervals DHCP reservations Addresses are assigned by MAC address in DHCP server Quickly Manage from 1 location Servers, printers… HTTP tcp/80 HTTPS tcp/443 Hyper text protocol Communication in the browser Can be used by other applications HTTP = in the clear HTTPS = encrypted SNMP upd/161 Simple Network Management Protocol Different versions V.1 structured tables, in the clear V.2 Data type enhancements, bulk transfers, still in clear V.3 Message integrity, Authentication, encryption Rdp tcp/3389 Remote Desktop Protocol On many windows systems Can connect to entire desktop or just application Clients for Win, MAcOS, Linux, Unix, iPhone NTP udp/123 Network Time Protocol Sets time for device Syncs all devices Used for Authentication You control when clocks are updated Very Accurate (better then 1 millisecond on local network) VOIP tcp/5060 and tcp/5061 (SIP Session Initiation Protocol) Voice over IP Signaling Doing all call Adds video, instant messaging, file transfer SMB Server Message Block tcp/445 Protocol used my Microsoft File Sharing Print Sharing Also called CIFS (Common Internet File System) PoP/Imap tcp/110 POP3 Basic Mail Transfer IMAP4 tcp/143 Includes management of email inbox from multiple clients. (desktop and iPhone) LDAP tcp/389 Lightweight Directory Access Protocol Store and receive data in a network directory LDAPS(LDAP Secure) tcp/636 Non-standard of ldap over SSL H.323 tcp/1720 Also VOIP ITU Telecommunication h.23 protocol series Does all all call things Early. But still used today.