Network Essentials Chapter 9

Network Essentials
TCP/IP Applications
Chapter 9

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Side ASide B
in the networking world any single communication btw computer and another computer
Transmission Control Protocol TCP
is how TCP/IP does connection-oriented communication.  TCP is by far the most common type of session on a typical TCP/IP network. Used because connection-oriented sessions are...
synchronize acknowledge finish reset
User Datagram Protocol (UDP)
runs a distant second place to TCP in terms of the number of applications that use it, but don't let that make you think UDP is not important.  UDP is perfect for the types of...
Trivial File Transfer Protocol (TFTP)  
ex of a protocol with which you can transfer files from one machine to another. But TFTP using UDP doesn't have any data protection so you would never use TFTP btw computers across...
ICMP Internet Control Message Protocol
The Internet Control Message Protocol (ICMP) is one of the core protocols of the Internet Protocol Suite. It is chiefly used by networked computers' operating systems to...
IGMP Internet Grup Management Protocol
IGMP is the glue that routers use to communicate with hosts to determine a group membership.The Internet Group Management Protocol (IGMP) is a communications protocol...
In computer networking, network address translation (NAT) is the process of modifying network address information in datagram (IP) packet headers while in transit across a traffic...
Port Number
a 16-bit value btw 0 and 65,535. Web servers use port no 80. Port nos 0-1023 are called well-known port numbers and are reserved for specific TCP/IP applications. Web client's source...
IANA Internet Assigned Numbers Authority     
recommends using only ports 49152-65535 as ephemeral port numbers.
Ephemeral port numbers
An ephemeral (short-lived) port is a transport protocol port for Internet Protocol (IP) communications allocated automatically from a predefined range by the TCP/IP stack...
Registered Ports
the port numbers from 1024 to 49151 are called registered ports.  Less-common TCP/IP apps can register their ports with the IANA
Well known port numbers
Regostered ports
Dynamic or private ports
socket or endpoint
ea pc on ea side of a session must keep track of the status of the communication.  In the tcp/ip world the session info stored in ram is called a socket or endpoint.
A session or connection
refers to the connection in general rather than specific to tcp/ip.  Many people still use the term session.terms for the connection data stored on a single computer. Terms for...
socket pairs or endpoints
terms for the connection data stored on two computers about the same connection
universal show me the endpoint utility. works at the command line; enables you to see active tcp/ip connections at a glance.netstat -an gives a list of your listening ports
open port or listening port
a socket that is prepared to respond to any ip packets destined for that socket's port number.  Every serving app has an open port. If you're running a web server on a pc, it will...
Process ID every running program on your computer gets a PID
Rules for Determining Good vs. Bad Communications
Memorize a bunch of known ports for common tcp/ip apps.Learn how to use netstat to see what's happening on your computer.  Learn to use switches such as -a, -n, and -o to help...
Hypertext Markup Language has been around for a long time and as a result has gone thru many versions.  Today many pages are being written in an updated html version called extensible...
Dynamic Naming system DNS
web site text addresses use this naming protocol
Hypertext Transfer Protocol HTTP
is the underlying protocol used by the web and it runs by default on tcp port 80. When you enter http:// aat the beginning of a web servThe problem with this is that web designers continue...
Web server
is a computer that delivers or serves up web pages.  Web servers listen on port 80, fetching requested html pages and sending them to browsers.  You can turn any computer...
Internet Information Services IIS
a MS app that enables you to set a max connection limit on your web server based on available bandwidth and memory.  This enables you to protect your network against an overwhelming...
Denial of Service DOS
malicious attack on a web site
Apache HTTP Server
unix/linux based os serves well over 50% of the web sites on the internet.  Apache is incredibly popular, runs on multi os, including windows and best of all, its free.  Apache...
Web clients
are the programs used to surf the Web.  A client program aka a web browser reads web pages supplied by the web server.
HTTPS Hypertest Transfer Protocol over SSL Secure Sockets Layer
uses TCP port 443. SSL is a protocol developed by Netscape for transmitting private docs over the inet. SSL works by using a public key to encrypt sensitive data.  This encrypted...
runs on tcp port 23 enabling you to connect to a telnet server and run commands on that server as if you were sitting right in front of it. Reqs username and password. Does not have...
Secure Shell (SSH)
replaced telnet and is a terminal emulation program that looks exactly like telnet but encrypts the data.
Telnet client
computer from which you log onto the remote server.
PuTTY is a free and open source terminal emulator application which can act as a client for the SSH, Telnet, rlogin, and raw TCP computing protocols. The name "PuTTY" has no...
Rlogin, RSH Remote Shell and RCP Remote Copy
These are three old school programs in the UNIX world.  The R stands for remote and like telnet and SSH, these programs provide remote access and control of servers.  Also...
SMTP Simple Mail Transfer Protocol
is used to send email. SMTP travels over TCP port 25 and is used by clients to send messages.
POP3 Post Office Protocol version 3
is one of the two protocols that receive email from SMTP servers.  POP3 uses TCP port 110. Most email clients use this protocol, although some use IMAP4.
IMAP4 Internet Message Access Protocol version 4
is an alternative to POP3. Like POP3, IMAP4 retrieves email from an email server. IMAP4 uses TCP port 143 and supports some features that are not supported in POP3. Ex. enables you...
FTP File Transfer Protocol
is the orig protocol used on the inet for transferring files. Although http can be used to transfer files as well, the transfer is often not as reliable or as fast as with ftp. ftp...
Review tool to help remember Internet Applications
http tcp port 80 the webhttps tcp port 443 the web securitytelnet tcp port 23 terminal emulationssh tcp port 22 secure terminal emulationsmtp tcp port 25 sending emailpop3 tcp port...

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