TCP & UDP Flashcards
POP3 Port
TCP 110
FTP Port
TCP 20 - Data
TCP 21 - Control Signals
SSH Port
TCP 22
Telnet Port
TCP 23
SMTP Port
TCP 25
HTTPS Port
TCP 443
HTTP Port
TCP 80
DNS Port
UDP 53
TCP 53
SNMP Port
UDP 161 - Agent
UDP 162 - Manager
Syslog Port
UDP 514
DHCP Port
UDP 67 - Server
UDP 68 - Client
TFTP Port
UDP 69
For applications like real-time voice and video, [TCP/UDP] is preferred.
UDP
For applications that require reliable communications, [TCP/UDP] is preferred.
TCP
Layer 4 ephemeral port range (according to IANA):
49152 - 65535
Layer 4 registered port range (according to IANA):
1024 - 49151
Layer 4 well-known port range (according to IANA):
0 - 1023
TCP four-way handshake order of messages (terminating a connection):
FIN ->
<- ACK
<- FIN
ACK ->
TCP three-way handshake order of messages (establishing a connection):
SYN ->
<- SYN-ACK
ACK ->
TCP: […] is used to indicate the sequence number of the next segment the host expects to receive.
Forward acknowledgement
TCP: A ‘[…]’ is used to dynamically adjust how large the window size is.
sliding window
The Layer 4 [source/destination] port number is randomly selected by the host that initiates the data exchange.
source
The Layer 4 destination port number indicates the […] Layer protocol.
Application
The TCP header […] field is used for flow control.
window size
