2.1: TCP and UDP ports and Protocols

Connection Oriented sessions

Every packet that is sent is checked for delivery.

First step of the TCP three way handshake

SYN

Second step of the TCP three way handshake

SYN ACK

Third step of the TCP three way handshake

ACK

SYN

Client computer attempts to initiate a session to a server with a synchornize packet of information.

SYN + ACK

The server responds to the client request by sending a synchronization/acknowledgment packet.

ACK

The client sends an acknowledgement packet to the server.

Flow control

Method that TCP uses to prevent a sender from overwhelming a server by sending too many requests.

Connectionless sessions

If a packet is dropped, it is not asked for again

HTTP Port

80

HTTPS port

443

Outbound port

point that allows communication to leave a network and go to an external destination

Inbound port

port on a device (like a computer, server, or router) that is used to receive incoming connections from other devices over a network.

Does SMTP send or receive email?

Sends email

Default SMTP port:

25

SMTP with SSL port

587

SMTP with TLS port

465

Does POP3 send or receive email?

Receive

Original Server port for POP3

110

POP3 default port

995

IMAP server port

143

IMAP secure port

993

POP3

Used by email clients to retrieve incoming email from a mail server.

IMAP

Enables messages to remain on the email server so they can be retrieved from any location.

Telnet is

Deprecated and insecure

File transfer protocol (FTP)

Allows computers to transfer files back and forth.

FTP server port

21

FTP is not secure, most orgs will use

SFTP or FTPS

SFTP port

989

FTPS port

990

Secure Shell (SSH)

Enables the remote control of computers and enables data to be exchanged between computers on a secure channel.

What port must be open on a server to access SSH?

22

Is SSH connection or connectionless

connection oriented

What does SSH utilize

TCP

Telnet

Provides remote access to other hosts using the command line interface.

Telnet port

23

You should usually ___ telnet

disable

How do you disable telnet

The turn windows features on or off window

How can you tell if telnet is disabled

Check the services console window. (Run > services.msc)

Dynamic Host Configuration Protocol (DHCP)

Used to automatically assign IP addresses to hosts.

SOHO

Small office Home office

What can a DHCP server assign?

Ip addresses, subnet masks, gateway addresses, DNS server.

DHCPv4 servers use port

67

DHCPv4 clients use port

68

Domain Name System (DNS)

Group of servers on the Internet that translates domain names to IP addresses.

DNS Server inbound port

53

Lightweight Directory Access Protocol (LDAP)

Used to access and maintain distributed directories of information, or Active Directory.

LDAP runs on inbound port

389

Secure LDAP runs on port

636

Remote Desktop Connection

Facilitates connections to remote computers and allows full remote control.

Remote Desktop Connection port

3389

Server Message Block (SMB)

Provides access to shared items such as files and printers.

SMB over TCP port

445

SMB over netBIOS/NetBT port

137/139

SMB was also referred to as

Common Internet File System (CIFS)

Simple Network Management Protocol

Standard for managing and monitoring devices on a network.

What are some thing SNMP manages?

Routers, Switches, UPS devices, computers

Network Management System

Main software that controls everything SNMP based

What protocol uses port 22

SSH

What protocol would be used for Streaming media

UDP

A user can recieve email but cannot sent any. Which protocol is not setup properly?

SMTP

HTTP can be converted into HTTPS using

SSL or TLS