Ports and Protocols

RDP

Remote Desktop Protocol

Apple Migrated from AFP to what protocol in which OS?

SMB2 in OS X 10.9

Port 22--SSH

a Unix-based TCP protocol port used to securely access a remote server. A secure replacement for older protocols. Commands are encrypted and authentication occurs using a digital certificate.

Port Number

a logical address used by applications or processes that are network based

Port 548--AFP

a proprietary file services protocol which offers file sharing services for Mac OS X. Uses both UDP and TCP

Error code 503 - Service Unavailable Connection Refused by Host occurs when?

access requires permission or a password is incorrect

NS

address of domain's name server

SOA

authoritative server for zone

How is the DHCP process started?

client send out a DHCPDISCOVER message on UDP 67 using broadcasting. *note that if the server is on a different subnet, a router must be configured to use DHCP-relay to forward the request

Port 445--SMB/CIFS

created for Windows 2000 to provide a direct path to TCP/IP without the need for the NetBIOS layer. Also not a secure

CNAME

creates an alias name for host

SRV

defines the server for specific purpose such as HTTP, FTP, and so on

What is the usage of TCP?

designed to enable two devices to establish and maintain a connection and communicate.

A

host name to an IPv4 address

AAAA

host name to an IPv6 address

MX

mail exchange server for domain

PTR

maps the address to the host name for reverse lookup

What are the disadvantages of Ports 137-139--NetBIOS/NetBT?

not secure and can give out information such as server name, domain, workgroup name, and account information

What is the usage of UDP?

provides minimal transport services, used mainly with gaming, voice, and video applications. also popular for tunneling.

How is port 3389--RDP accessed?

remote computer must be turned on and must have network connection with Remote Desktop application running.

What does DNS work with?

root servers, also known as DNS resolvers, to answer basic queries on where a specific site is located

Port 427--SLP

service discovery protocol used to find services in networks and also used to announce services on a local network. is a packet-oriented protocol using both UDP and TCP.

Protocols

set of rules that are followed in order to provide communication between devices

What does the error codes 404 and 503 indicate?

the server is busy or there is too much traffic

What is DHCP used for?

to automatically assign TCP/IP addressing info to computers that request it. Not only sends IP the address, but also the subnet mask, the gateway address, and any DNS info it has.

Ports 137-139--NetBIOS/NetBT

use TCP for communications and provide methods for network file and print sharing. NetBIOS protocols.

Ports 20/21--FTP

used to transfer files between two devices over a network. Authentication is made of both username and passwords sent in clear text. TCP port 20 is used to send, TCP port 21 is used to recieve.

Port 80--HTTP

uses TCP to transmit. It is stateless because each command is executed without knowing any command sent before it. It defines how messages and error codes are formatted and transmitted.

Port 3389--RDP

uses TCP to view and control another computer running Windows on a network.

Port 53--DNS

uses both TCP and UDP to resolve UNC hostnames into IP addresses used to locate websites. Hierarchical distributed naming system for computers when connected to internet.

Port 110--POP3

uses port 110 to download e-mails from a server and then delete it. This means the e-mail is no longer available from server, although some systems are designed to keep a copy for some time.

Port 143--IMAP

uses port 143 to store emails on a remote server. Usually a better option than POP3 because emails can be accessed from multiple devices and locations.

Port 443--HTTPS

uses port 443 to provide a SSL Certificate to encrypt the transfer of data on a webpage. Is a combination of the SSL protocol and TLS protocol.

How is a DSN zone file constructed?

using resource records stored in zone files

What is the latest version of IMAP?

version 4

What are two of the most common HTTP error codes?

•404 - File Not Found •502 - Service Temporarily Overloaded

DSN root servers manage the top-level domains. What are they?

•Com- commercial businesses •Edu- educational organizations •Gov- government organizations •Mil- military organizations •Net- networking organizations such as ISPs •Org- noncommercial organizations •Int- international organizations such as NATO

Characteristics of a zone or domain

•SOA •NS •A •MX •AAAA •SRV •PTR •CNAME

What are port 427--SLP roles?

•UAs that search for services •SAs that announce services •DAs that cache services info

What are some characteristics of port 143--IMAP?

•any computer can be used to view email •e-mails are stored on the server •server space can be limited by provider

Protocols cover what specifications?

•communication timing •packet sizes •length of transmission periods •other specifications that allow multiple technologies to coexist and provide networking communication for a specific purpose and environment

Disadvantages of using UDP:

•delivery can be out of order and unreliable •no protection from duplication exist •no end-to-end connections •no congestion or flow control

Advantages of using TCP:

•guaranteed delivery, connection-oriented •data can be transferred in full duplex on a single connection •manages flow control •meant to be error-free (handles retransmission)

Advantages of using UDP:

•has lower bandwidth than TCP •can be broadcast •multicast applications are built on top of UDP

What is the process the client goes through with the server during DHCP?

•initializing •selecting •requesting •binding •renewing •rebinding

What are a few common characteristics of port 110--POP3?

•only one computer can be used to retrieve e-mail •e-mails are stored on the local computer

Disadvantages of using TCP:

•slower than UDP •a complex protocol to set up and maintain

DHCP

Dynamic Host Configuration Protocol

FTP

File Transfer Protocol

LDAP

Lightweight Directory Access Protocol

What is the complete name for a specific computer or host on the internet?

FQDN

FQDN

Fully Qualified Domain Name

HTTP

Hypertext Transfer Protocol

HTTPS

Hypertext Transfer Protocol Secure

IMAP

Internet Message Access Protocol

Port 3389--RDP is what type of protocol and what does it provide?

It is a Microsoft protocol and it provides encryption, print redirection,remote control, network load balancing, and access to clipboard.

AFP

Apple Filing Protocol

There are how many ports in use today?

65,535

CIFS

Common Internet File System

SSH

Secure Shell

SMB

Server Message Block

SLP

Service Location Protocol

SMTP

Simple Mail Transfer Protocol

SNMP

Simple Network Management Protocol

What can cause a delay in TCP?

TCP can break down large data packets and resend and lost packets

Port 23--Telnet

TCP port text-based terminal emulation program used to connect toba remote computer. Historically, it was used to maintain, update, and configure routers, firewalls, and other remote internet devices. Is not a secure protocol and should be blocked.

Port 25--SMTP

TCP port used for the transmission of e-mail reliably and efficiently. Used for sending, but recieving is limited and cannot queue messages, so SMTP is usually utilized with POP3 and IMAP for message retrievals.