Overview of TCP/UDP Protocols and Well-Known Ports

FIN

No more data from sender

ACK

Acknowledgment field significant

PSH

Push function

SYN

Synchronize sequence numbers

RST

Reset the connection

Well-known ports

Numbers 0 to 1023

Registered ports

Numbers 1024 to 49151

Dynamic or private ports

Numbers 49152 to 65535

LISTEN

The local connection is waiting for a connection request from any remote device.

ESTABLISHED

The connection is open, and data may be exchanged

through the connection.

ESTABLISHED

This is the normal state for the data-transfer phase of the connection.

CLOSE-WAIT

The connection is closed, but is waiting for a termination request from the local user.

TIME-WAIT

The local connection is waiting a default period of time after sending a connection termination request before closing the connection.

How much time does the state TIME-WAIT normally last?

30 to 120 seconds

SYN-SENT

The local connection is waiting for a response after sending a connection request. The connection should transition quickly through this state

SYN_RECEIVED

The local connection is waiting for a confirming connection request acknowledgment. The connection should transition quickly through this state.

TCP

Connection-oriented protocol, described in RFC 793, incurs additional overhead to gain functions.

UDP

Simple, connectionless protocol, described in RFC 768, has the advantage of providing low-overhead data delivery.

Segment

The pieces of communication in TCP.

Datagram

The pieces of communication in UDP.

File Transfer Protocol (FTP) Data

20

File Transfer protocol (FTP) control

21

telnet

23

simple mail transfer protocol (smtp)

25

trivial file transfer protocol (tftp)

69

hypertext transfer protocol (http)

80

post office protocol 3 (pop3)

110

internet relay chat (irc)

194

secure http (https)

443

routing information protocol (rip)

520

DNS

53

SNMP

161

AOL instatnt messenger, IRC

531

MS SQL

1433

WAP (MMS)

2948

RADIUS authentication protocol

1812

MSN messenger

1863

cisco skinny client control protocol (SCCP, used in VoIP applications)

2000

real-time transport protocol (rtp, a voice and video transport protocol)

5004

session initiation protocol (SIP, used in Vo IP applications)

5060

alternate http (last 8)

8008

alternate http (last 0)

8080