Intro to IP and Ports Flashcards
IP is like a series of moving vans
- Network topology is the road (ethernet, DSL, cabling)
- the trucks are IP (roads designed for this truck)
- the boxes inside hold your data (TCP/UDP)
- inside the boxes are also application info
What is multiplexing?
sending may different applications across the network simultaneously between the same devices.
TCP is connection oriented, what does that mean?
there is a formal set up and tear down process.
TCP can acknowledge that the recipient has received data, which UDP cannot. what is this called?
Reliable Delivery
What is a TCP acknowledgement?
TCP ACK
What does a sending device do if it does not receive a TCP ACK?
resend the data
UDP is connectionless, meaning…?
there is no formal open or close, no acknowledgement. no warning that data is coming or when it will stop.
Can TCP or UDP use flow control?
TCP can because it is a connection oriented protocol which allows the recipient to perform flow control.
what range is non ephemeral port numbers?
0 - 1,024
What range are ephemeral ports?
1,024 - 65,535
Port numbers are for communication, not security
service port numbers need to be well known
TCP and UDP port numbers are not the same, but ranges are
TCP and UDP use port 80 for different things
FTP use and port number?
tcp/20 (active mode data)
tcp/21 (control)
file transfer between systems. generic and not specific to an OS
SSH / Secure Shell use and port number?
tcp/22, text based console communication. Encrpyted communication link, also allows for encrypted file communication
STFP use and port
tcp/22, generic file transfer with security alone an encrypted network.
telnet
tcp/23, non encrpted communication, looks identical to SSH but telnet is sent in the clear (non encrpyted).
SMTP using plaintext
SMTP using TLS encryption
tcp/25 (SMTP using plaintext)
tcp/587 (SMTP using TLS)
Simple Mail Transfer Protocol, server to server email transfer. Also used from client devices sending to mail server.
Other protocols are used for clients to receive email, IMAP or POP3
DNS (fqdn)
udp/53, larger transfers may use tcp/53