Ports and Protocols
Common Ports Unwrapped! Remote Access, Files and the City Services
9:36Coming soon
A security audit lands on Friday with four findings, and every one is just a door number marked "open, no lock": 23, 21, 69, 161. This is the second Common Ports lesson: every port left on the exam's list, sorted into three streets of Byte City, and one rule that makes fifteen numbers stick — many doors have a locked twin.
You'll learn
- Remote access: 22 (SSH, the staff entrance with its own lock), 23 (Telnet, the same door with no lock), 3389 (RDP, the whole desk carried to you)
- Files: 20/21 (FTP, two doors one conversation), 22 again (SFTP, files inside SSH's lock), 69 (TFTP, the bullhorn hatch), 445 (SMB, the filing room that must never face the road)
- The city services: 67/68 (DHCP), 123 (NTP), 161/162 (SNMP and traps), 514 (syslog), 389/636 (LDAP and LDAPS), 5060/5061 (SIP), 1433 (SQL Server)
- The twins rule: 23→22, 21→22, 389→636, 5060→5061, and 80→443 from part one
- The bullhorn set: which of these doors expect UDP, and why
- The real thing: testing a switch on port 23, turning Telnet off and SSH on, and closing all four audit findings
- Exam corner: managing a switch without clear-text credentials — which port?
Chapters
- 0:00The audit list
- 0:40The map of part two: three streets
- 1:06The rule: locked twins
- 1:43Remote access: 22, 23, 3389
- 2:50Files: 20/21, 22, 69, 445
- 4:24The city services: 67/68, 123, 161/162, 514, 389/636, 5060/5061, 1433
- 5:52The real names: the list
- 6:52The twins and the bullhorn set
- 7:53The real thing: Telnet off, SSH on
- 8:52Exam corner
- 9:13Recap and next time
Exam objectives: CompTIA Network+ N10-009: 1.4 (common ports and protocols: 20/21, 22, 23, 67/68, 69, 123, 161/162, 389, 445, 514, 636, 1433, 3389, 5060/5061), 4.3 (secure versus insecure protocols: Telnet→SSH, FTP→SFTP, SNMPv3, LDAPS), 5.5 (Test-NetConnection).
Byte City is not affiliated with or endorsed by CompTIA.