Ports & Protocols 1

Answer 1

1.1 Explain the purposes and uses of ports and protocols.
Protocols and Ports
SSH 22
Used as a method for remote login from one computer to another in a secure manner.
Client uses the public key of the remote computer (SSH Server), symmetric
Process
Client initiates connection
Server sends public key
Client/Server exchange session key and start secure communication
Client logs on
DNS 53
SMTP 25
SMTP is allocated for UDP and TCP
Most often implemented with TCP
Microsoft does not use UDP
SFTP 22
FTP 20,21
TFTP 69
TELNET 23
Demo Telnet
DHCP 67, 68
HTTP 80
Show browser connection
Use Wireshark to verify Port 80 connection
HTTPS 443
SNMP 161
RDP 3389
Demo connection from Client01 to Client02
NTP 123
SIP 5060, 5061
Used for voice communications intially (1996) but later expanded
Now used for voice, video, IM, presence to name a few
SMB 445
Application layer
A version of CIFS
Accessing Windows shares
Printers
Files
Serial ports
TCP port 445
NetBIOS UDP port 137 & 138
POP 110
TCP port 110
IMAP 143
TCP port 143
LDAP 389
Used as a replacement to X.500's Directory Access Protocol (DAP)
LDAP allowed for accessing directories over TCP/IP
Demo with Wireshark running on DC01
LDAPS 636
Uses public key cryptology via SSL to secure access to directories over TCP/IP
Demo with Wireshark running on DC01
H.323 1720
Used initally used(1996) for video conferencing but was expanded
Now used for audio/video/data teleconferencing communications over TCP/IP
A convergence protocol
Used with VoIP as well as SIP
H.323 = International Telecommunications Union
SIP = IETF
Used in a large number of legacy systems
Protocol types
ICMP
Error messages
Diagnostics
Flow Control
Typically not used for data exchange
UDP
TCP
IP
Connection-oriented vs. connectionless

Question 2

SSH

Answer 2

SSH 22
Used as a method for remote login from one computer to another in a secure manner.
Client uses the public key of the remote computer (SSH Server), symmetric
Process
Client initiates connection
Server sends public key
Client/Server exchange session key and start secure communication
Client logs on

Question 3

DNS

Answer 3

DNS 53