Mod 6
Well Known Ports
0-1023; mainly used for serving data and are assigned for all commonly used applications.
Private Ports
49,152-65,535
Routing Table
A list of networks and paths the router references for decisions on packet forwarding.
TCP/IP Model
A practical implementation of the OSI Model.
Protocol Data Unit (PDU)
A unit of information passed as self-contained data structure from one layer to another on its way up or down the network protocol stack.
A - Host Records
All of the IPv4 hosts with names and IP addresses on the domain, to include websites
Lightweight Directory Access Protocol (LDAP)
Application Layer protocol used to structure information on a directory server
Class C
Class used by small corporations and personal networks with 256 hosts available.
BOOTP
DHCP improved this protocol but uses the same ports.
Subnet Mask
Defines where the network ID stops and the host ID begins.
Routers
Device that works at Layer 3 (OSI) or Internet Layer (TCP/IP Protocol Suite)
Label Edge Routers (LERs)
Entry and exit point of an MPLS domain, they add and remove labels.
Repeaters and Hubs
Hardware that is used at the Physical Layer (Layer 1)
Management Information Base (MIB)
Information in SNMP is not standard and is defined in what is called the ______.
Physical Layer (Layer 1)
Layer where communications between devices actually take place.
trap
Message sent to the SNMP server if a change in an agents device status occurs.
Bridge Loop
Multiple paths are available for frames to travel between switches, which can cause an endless loop.
Start of Authority (SOA)
One DNS server is the best source of information for the zone. Acts as the primary DNS server in many environments
Host ID
Portion of the IP address that identifies a particular host on a network segment. It must be unique within the network ID.
Time Division Multiplexing (TDM)
Process of combing analog or digital signals with each signal having its own time slot to transmit or receive data via a single carrier.
TCP & UDP
Protocols used by the Transport Layer (Layer 4)
Network Interface Card (NIC)
Provides the interface between a computer and the network medium. AKA: Network Adapter
Response Indication
That the remote host is reachable and how long it took the message to make the round trip from sender to receiver.
Four Layers of the TCP/IP Protocol Suite
1. Application: Data 2. Transport: UDP Header, UDP Data 3. Internet: IP Header, IP Data 4. Network Interface: Frame Header, Frame Data, Frame Footer.
Fields Inside of a Packet
1. Starting Flag 2. Header 3. Data 4. Error Check 5. Ending Flag
Registered Ports
1024-49,151
MAC Address
48 bits (6 Byte) hexadecimal address that is burned into the NIC and is used in the delivery of information on an Ethernet network. AKA: Ethernet hardware address, burned in address, physical address.
# of Ports
65,536 - Start a 0 when counting so the last port is 65,535.
Open Systems Interconnect (OSI) Reference Model
7 layer model created by ISO to aid manufacturers in creating network devices and software that could work together
Open Systems Interconnect (OSI) Layers
7. Application Layer 6. Presentation Layer 5. Session Layer 4. Transport Layer 3. Network Layer 2. Data Link Layer 1. Physical Layer
Host Portion
A Binary 0 signifies that the corresponding bit in the IP address belongs to....
Network Portion
A Binary 1 signifies that the corresponding bit in the IP address belongs to....
Data Link Connection Identifier (DLCI)
A channel number that is attached to Frame Relay data frames to tell the network how to route data.
MAC Address Table (MAT)
A copy of the CAM that is in human readable format.
Repeater
A device that receives a signal and regenerates it. It will remove any noise by recreating the original transmission. This device has no intelligence.
Domain Name System (DNS)
A distributed name system that contains services to map computer names to IP addresses. Domains exist at different levels and connect in a hierarchy starting with the root.
ANDing
A form of Boolean logic that is utilized by a routing device to identify the network in which a particular IP address resides.
Octet
A group of 8 Binary digits (bits), or one Byte.
Diffie-Hellman
A key exchange that takes place allowing two devices with no prior communication to jointly establish a shared secret key over an insecure channel, like the Internet. Key can then be used to encrypt subsequent communications using a symmetric key cipher.
Internet Protocol
A protocol that allows data to be routed from one network device to another.
File Transfer Protocol (FTP)
A robust file manipulation application used for exchanging and manipulating files over a TCP based computer network. Method of establishing a secure communication channel. Has two methods of operation: active and passive
Address Field
An 8 bit field used to indicate different versions of HDLC used on a network or to annotate the receiving machine.
CNAME - Canonical Name
An alias (EX: ws1 can also be reached via the alias mypc.jcac.local). www is a common alias for web hosting.
Internet Control Message Protocol (ICMP)
An error reporting mechanism for the IP protocol. Sends error reports back to the originator of the datagram if a problem is encountered along the transmission path. Works at the Network Layer (OSI Layer 3) or the Internet Layer (TCP/IP Suite).
User Datagram Protocol (UDP)
An unreliable, connection-less protocol that does not guarantee data transmission. Has a fixed 8 byte header. Uses port addressing.
Step 3 Three Way Handshake
Computer A sends an acknowledgement packet (ACK) and a connection is established. Flag value of 10. Client to server.
Step 1 Three Way Handshake
Computer A sends computer B a request for synchronization packet (SYN) to indicate a desire to communicate. Flag value of 2. Client to server.
Step 2 Three Way Handshake
Computer B sends computer A a request acknowledgement packet (SYN/ACK) when the requested service is available. Flag value of 12. Server to client.
Zone Transfers
Conducted when a primary DNS server transfers its cache/database to a secondary or back up DNS server. Uses port 53 and TCP.
Committed Information Rate (CIR)
Congestion control with Frame Relay works by providing a guaranteed minimum bandwidth for each user.
Multi-Protocol Label Switching (MPLS)
Considered a layer 2.5 technology, allows routers to label data and use specific connections and paths. Works with other packet switched protocols by adding short (4 byte) path labels between the Layers 2 and 3 (reason called 2.5) headers, which are read instead of longer network addresses.
IPv4 Address
Consists of a set of four numbers, each of which can range from 0 to 255 and is known as an octet.
Resource Records
Contain information about servers, hosts, and even services.
Starting and Ending Flags
Contain unique bit patterns to mark the beginning and ending of the packet.
Header Field
Contains addressing information and also can contain: 1. Sequence numbers for error and flow control 2. Indicators of the next protocol layer 3. Type of service indicators 4. Fragmentation indicators 5. Compression indicators 6. Other indicators
Root Zone File
Contains information on all Top-Level Domains (TLDs) that reside at the highest level of the hierarchy under root.
Project 802
Created specifications that define connection technologies such as 802.3 for Ethernet and 802.11 for Wireless.
Fully Qualified Domain Name (FQDN)
DNS (hierarchical) namespace, is the structure of the domains when they are combined. It specifies and address' exact location in the DNS hierarchy. It specifies all domain levels, including the root domain, top level domain, parent domain, and host.
Recursive
DNS Server makes additional queries to other DNS servers on behalf of the client, in order to find the requested name to IP resolution.
Real-time Transport Protocol (RTP)
Defines how voice or data packets are transported over the Internet. A foundation of VOIP. Uses UDP as its a Transport Layer protocol due to being tolerable to packet loss and favoring timeliness over reliability. Most VOIP runs on top of ____.
Ethernet Framing
Defines the meaning of the bits transmitted and received over a network. Enables the bits to be interpreted correctly.
Amplifier
Device developed for strengthening a signal to extend transmission distance. Problem was that it would also strengthen any noise it received along with the intended transmission.
Switches
Devices designed to increase the performance of a network. They decide on which port to send a signal instead of broadcasting it out to every port. They break up (define) collision domains but not broadcast domains.
Code Division Multiple Access (CDMA)
Digitizes the data and then spreads it out over the entire available bandwidth on the carrier. A form of spread spectrum which means that data is sent in small pieces over a number of the discrete frequencies available for use at any time in the specified range.
Transport Layer Security (TLS)
Does not have the restrictions that SSL does, and is used to secure additional protocols VoIP and VPNs.
Host
Each device (computer, router, or other device with a connection to the network) on a TCP/IP network.
Ethernet
Easy to install, scalable, inexpensive to implement, and supports transmission speeds from 10 megabits per second to 10 gigabits per second while being able to operate in half-duplex or full-duplex modes.
Spanning Tree Protocol (STP)
Enables switches to detect and fix bridge loops by blocking redundant ports.
High Level Data Link Control (HDLC)
Encapsulation method for data on serial links that will not encapsulate multiple network protocols on the same link and, because of this, carries no identification of the type of protocol being carried. It is proprietary for each vendor that uses it. The default interface that is used for CISCO routers. Must be on both ends of the communication in order for it to work.
Socket
Endpoint of a communications flow
Default Gateway
Every LAN to be connected to another LAN requires a router connection known as....
Hypertext Transfer Protocol Secure (HTTPS)
Extension of the HTTP protocol that rides over the Secure Sockets Layer (SSL) or Transport Layer Security (TLS) that provides security to a web session.
32 - Given CIDR = y y - 2 = x
Formula used to determine the number of assignable hosts for each subnet of a network (x).
Given CIDR - Default CIDR = y 2^y = x
Formula used to determine the number of subnets in a given network (x).
Packet Switched Protocols
Frame Relay and X.25
Routers
Hardware devices implemented at the Network Layer (Layer 3) because they forward packets based on logical addressing.
Switches
Hardware devices that are used to implement the Data Link Layer (Layer 2)
IEEE
Institute of Electrical and Electronics Engineers
Router
Interconnects local or wide area networks. Primary function is to determine the next network to which a packet is sent by scanning the destination IP address and searching for the path the packet needs to take. They break up broadcast domains by default and they also break up collision domains. Use logical addressing.
NIC Function
It prepares, sends, and controls data flow across the network.
OSI Model Layer 3 TCP/IP Suite Internet Layer
Layer of the OSI Model and TCP/IP Suite that routers function at.
OSI Model Layer 2 TCP/IP Suite Network Interface Layer
Layer of the OSI Model and TCP/IP Suite that switches function at.
OSI Model Layer 1 TCP/IP Suite Network Interface Layer
Layer of the OSI Model and the TCP/IP Suite that Repeaters function at.
OSI Model Layer 2 TCP/IP Suite Network Interface Layer
Layer of the OSI Model and the TCP/IP Suite that the NIC functions at.
Transport Layer (Layer 4)
Layer responsible for breaking data into pieces small enough to transmit (segments). Each segment is given a sequence number so the original data can be reassembled in proper order after being received by the destination.
Network Layer (Layer 3)
Layer responsible for the logical addressing and routing of messages to their proper final destination. Applies logical addressing to each packet.
Physical Layer (Layer 1)
Layer that consists of actual network transmission media such as cable or radio waves.
Data Link Layer (Layer 2)
Layer that provides a reliable method of transmitting data across the communication link. Broken up into two sub layers.
Link Lights
Light Emitting Diodes (LEDs) of various colors, each meaning something different about the current connection. They are used for diagnostics and trouble shooting.
Address Resolution Protocol (ARP)
Low level protocol used to associate the hardware 48-bit MAC address to the 32-bit IP address on a physical network.
Media Access Control (MAC)
Lower sub layer that is responsible for mapping between logical and physical addressing and access to the network media. Physical address.
Root Name Servers
Machines that provide access to the Root Zone File
Repeaters
Made it possible to transmit signals over a large distance. EX: Transoceanic Cable.
Transport Layer (Layer 4)
Manages data delivery between systems or hosts. Protocols can be connection-less or connection-oriented.
PTR - Pointer Record
Maps IP addresses to names for reverse lookups
Uplink Port
Method developed to electronically switch the transmit and receive wires inside the equipment in order to alleviate the need for different cable.
Wave Distribution Multiplexing (WDM)
Method of multiplexing data from two or more inputs and transmitting them over the same fiber-optic cable where each input is propagated on its own wavelength (color). The only method of multiplexing to use light.
Full-Duplex Ethernet
Mode of operation allowing simultaneous communication between a pair of stations. The link between the stations must use a point to point media segment.
Client/Server Model
Model that TCP/IP services primarily operate in.
Hubs
Multi-port repeaters that receive a digital signal, regenerate it, and then broadcast that signal to all connected ports. All devices that are connected are in the same collision and broadcast domain.
Circuit Switching
Networking method that establishes a fixed path between the transmitting and receiving stations. Bandwidth is constant for the duration of the transmission and the communications path cannot be used by anyone else until the circuit is released and reissued.
PPP
Non proprietary protocol technology that is used to connect WAN links when equipment is purchased from different vendors.
169.254.0.0 /16 (APIPA)
Non-routable IP address range that is used by Windows machines when they are not able to contact a DHCP server the host will assign itself an address within this range.
Private IP Ranges
Non-routable addresses that have been reserved for private networks and cannot be routed across the internet.
Default Route
Often used to send traffic to a gateway of last resort for forwarding if there is no entry for a destination. IPv4 has it. IPv6 does not have it.
H.323
Older VOIP standard. Handles VOIP call initiation, setup and delivery. Uses RTP to support video teleconferencing, security, and multi casting.
x.25
One of the oldest packet-switched services available, it was developed before the OSI model. Created a universal and global packet-switched network. Used in the 1980s in ATMs by banks. Is a very slow but reliable service.
Session Initiation Protocol (SIP)
One of two main VOIP standards. Newer than H.323. Handles VOIP call initiation, setup and delivery. Uses RTP to support video teleconferencing, security, and multi casting.
Frame Relay
Packet switched technology that emerged in the early 1990s. Assumes that modern networking facilities and equipment is less error prone that in the past; therefore no error checking overhead is used along the transmission path. No error checking is done, that is the responsibility of the endpoints.
-l
Ping option on a Windows host that will allow you to set the size of the ping packet.
-t
Ping option on a Windows host that will cause the system to continue pinging until it is interrupted with a CTRL + C.
Network ID
Portion of the IP address starting from the left that identifies the network segment on which a host is located.
Frequency Division Multiplexing (FDM)
Process of combining analog or digital signals with each signal having its own frequency to operate within. Each input is assigned its own frequency.
Multiplexing
Process of combining and transmitting multiple analog or digital signals via a single transmission medium.
Three Way Handshake
Process used to establish a logical connection prior to the transmission of data, which is maintained throughout the entire communications session.
Automatic Private IP Addressing (APIPA)
Process when a Windows machine will use the 169.254.0.0 /16 IP address. It will allow a Windows machine to access the LAN but not the WAN (Internet).
Skype
Proprietary VOIP solution that is a peer to peer solution. Security is provided through a proprietary encryption standard.
Data
Protocol Data Unit (PDU) for the Application Layer (Layer 7).
Frame
Protocol Data Unit (PDU) for the Data Link Layer (Layer 2)
Packet
Protocol Data Unit (PDU) for the Network Layer (Layer 3)
Bit
Protocol Data Unit (PDU) for the Physical Layer (Layer 1)
Data
Protocol Data Unit (PDU) for the Presentation Layer (Layer 6)
Data
Protocol Data Unit (PDU) for the Session Layer (Layer 5)
Segment
Protocol Data Unit (PDU) for the Transport Layer (Layer 4)
Secure Shell (SSH)
Protocol that allows data to be exchanged using a secure channel between two networked devices.
Dynamic Host Configuration Protocol (DHCP)
Protocol used by a host to obtain an IP address from a ____ server. ____ server manages a pool of IP addresses and information about client configuration parameters such as default gateway, domain name, and name servers.
Internet Group Management Protocol (IGMP)
Protocol used with IP multicast. Multicast addresses are assigned based on traffic type, or group, not to individual hosts.
Frame Check Sequence
Provides a method for the receiving device to determine if the frame experienced transmission errors.
Network Adapter
Provides the interface between a computer and the network medium. AKA: Network Interface Card (NIC)
Transmission Control Protocol (TCP)
Reliable, connection-oriented Transport Layer protocol that accepts data of any length from upper-layer protocols and breaks them into segments. Header can be 20-60 bytes in length. Uses port addressing.
Packet Assembler/Disassembler (PAD)
Required to implement X.25 protocol.
Presentation Layer (Layer 6)
Responsible for presenting the data at the destination with the same meaning and appearance as it had at the source.
Label Switch Routers (LSRs)
Routers that simply forward traffic based on label information.
Static Routes
Routing table entry that is entered manually.
Learned Routes
Routing table entry that is learned and maintained through information from other routers.
Protocols
Rules that govern a convention or standard that enables data transfer between two computing endpoints.
Linux Default Ping
Sends 4 packets
Windows Default Ping
Sends 5 packets
SRV - Service Record
Services can be named and linked to an A record
Simplex
Session Layer (Layer 5) session in which communications occur in only one direction. EX: Sending an Email.
Half-Duplex
Session Layer (Layer 5) session in which communications occur in two directions but not at the same time. EX: Sending an Email and Receiving a Reply.
Full-Duplex
Session Layer (Layer 5) session in which communications occur in two directions simultaneously. EX: Chat Session.
Session Layer (Layer 5)
Sets up, coordinates, and terminates conversations, exchanges, and dialogues between devices across a network.
Trivial File Transfer Protocol (TFTP)
Simple protocol that only provides for the reading and writing of files or mail. Does not require a login or password to transfer data from a device to a server.
DHCP Process
Steps (DORA): 1. Discover 2. Offer 3. Request 4. Acknowledge
DNS Servers
Store information about a portion of the domain name space called a zone
DNS Caching
Storing responses allowing a DNS server to respond to multiple queries more quickly for a previously resolved domain or host.
Sponsored TLD (sTLD)
Subsets of gTLD, sites that are sponsored by an organization. EX: .mil, .gov, .edu
Generic TLD (gTLD)
TLD with three or more characters EX: .com, .net, .org
Content Addressable Memory (CAM)
Table built with the source MAC address is used to learn and associate MAC addresses of devices to attached ports. It enables the switch to forward frames based on physical address. Its operation is what differentiates a switch from a hub. Read by the computer.
Packet Switching
Technology based on transmitting packets (blocks of data in frame format) via multiple paths at a time.
Supernetting
The opposite of subnetting, in that network bits are taken back and utilized as host bits (Decreases networks, Increases Hosts)
Hypertext Transfer Protocol (HTTP)
The set of rules for exchanging files (text, graphic images, sound, video, and other multimedia files) from server to client and vice versa. Allows information exchange in a web based environment, and is the primary protocol of the WWW.
Ethernet Standard 802.3
The worlds most popular type of LAN defined by the Institute of Electrical and Electronics Engineers (IEEE).
netstat
Tool used to view socket information that is stored in RAM
Backward Explicit Congestion Notification (BECN)
Transmitted by destination terminal requesting the source terminal send data more slowly.
Forward Explicit Congestion Notification (FECN)
Transmitted by source (sending) terminal requesting the destination (receiving) terminal slow down its requests for data.
Country Code TLD (ccTLD)
Two letter country codes. EX: .nz (New Zealand), .au (Australia), .cn (China), .ru (Russia)
Remote Login (Rlogin)
UNIX software utility often used as an alternative to telnet which allows a user on a UNIX host to log in to another UNIX host over a TCP/IP network.
ifconfig
Unix based system command used to both display and change interface parameters to include IP addresses. Stands for Interface Configuration.
Logical Link Control (LLC)
Upper sub layer that handles error checking and flow control between the sender and receiver across a network. Also responsible for communicating with the Network Layer.
Internet Message Access Protocol version 4 (IMAP4)
Used to retrieve email from a mail server. Also enables a user to search through messages based on keywords and select which messages the user wishes to download to their local device, also supports folders to organize email on the server.
Unnumbered Frames
Used to send and receive acknowledgments for I and S-Frames, identified with 00000011
Simple Mail Transport Protocol (SMTP)
Used to send mail messages across a network and is the basis for Internet email.
Active Mode (FTP)
Uses two three way handshakes. The first is initiated by the client, the second is initiated from port 20 by the server which is outside of the network. Problem is that the second 3 way handshake is initiated from outside of the network.
Passive Mode (FTP)
Uses two three way handshakes. They are both initiated by the client and are always received on port 21 by the server. Everything is done within the network.
traceroute
Utility that uses ICMP to send messages and then uses the returning ICMP Time Exceeded (Time to Live - TTL) error messages to identify routers from source to destination.
Ping
Utility that uses the ICMP messages Echo (Request) and Echo Reply to request a response from a remote host to verify if it is available for communication.
Child Domain
www.googlemail.1.google.com - The 1 portion of the address is called the ______. Can have up to 32 of these domains.
Root Domain
www.nsa.gov. - The . portion of the address (it is implied at the end) is called the ______.
Top Level Domain
www.nsa.gov. - The gov portion of the address is called the ______.
Host
www.nsa.gov. - The www portion of this address is called the ____.
Parent Domain
www.nsa.gov. - the nsa portion of the address is called the ____.
Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
Used by half-duplex Ethernet as its media access control protocol. It acts like a traffic cop and is located on the NIC. Provides for collision detection and recovery by listening to the network after transmission to see if a collision occurred in transit.
Supervisory Frames
Used for error and flow control. They contain, send and receive sequence numbers, identified with 00000001
Voice Over IP (VOIP)
Used for the transmission of voice through the Internet or other packet-switched networks.
Subnetting
Used to break larger networks into smaller networks, each referred to as a subnetwork or subnet. Host bits are taken and utilized as network bits (Increases networks, Decreases hosts)
Switches
Used to eliminate the number of collisions on an Ethernet network. At Layer 2 they break up collision domains but they do not stop or break up IP broadcast traffic sent by network nodes in a respective broadcast domain. They direct traffic based on the source and destination MAC addresses attached to individual frames. They are designed to increase the efficiency of the network.
DNS Forward Servers
Used to forward DNS queries to DNS servers outside of the network.
MX - Mail Exchange
Used to identify mail servers
Simple Network Management Protocol (SNMP)
Used to manage and collect statistical network data such performance statistics from remote devices through polling.
Post Office Protocol version 3 (POP3)
Used to retrieve email from a mail server.
Internet Protocol (IP) Address
The primary protocol that is used by the Internet.
Anycast Addressing
maps traffic to the nearest host providing a specific service.
Time Division Multiple Access (TDMA)
A satellite and cellular technology that interweaves multiple digital signals by dividing each channel into sub-channels, providing service to multiple users simultaneously. If a time slot is not used then it will be allocated to another input so that it can be used.
IP Address Classes
A. 0-127; 255.0.0.0; CIDR /8 B. 128-191; 255.255.0.0; CIDR /16 C. 192-223; 255.255.255.0; CIDR /24 D. 224-239; Multicast Addressing E. 240-255; Experimental/Dead Range
Mutual Authentication
Ability to authenticate the client machine along with the server. Both SSL and TLS have the ability to use this but it is rare.
Bridging
Ability to connect networks with different media types. Ability enabled by switches. It is performed at the hardware level and use physical addressing.
DHCP Renewal
Address issued is used in terms of a lease, which usually lasts a few days. It is renewed through the DORA process and the same address will be reissued unless another computer has taken the address.
127.0.0.0 /8 (Loopback Address)
Address range that is used to test a NIC's ability to send or receive traffic. Range that would be pinged in order to test the IP stack functionality of a host computer.
Ports
Addressing method used by the Transport Layer (Layer 4)
Multicast Addressing
Addressing used to send traffic to a group of hosts or recipients.
Unicast Addressing
Addressing used to send traffic to a single host or destination.
Broadcast Addressing
Addressing used to send traffic to everyone on a LAN.
Half-Duplex Ethernet
All devices on this network risk collisions between the frames they send because they are on a shared Ethernet channel, this is a collision domain.
AAAA - IPv6 Host Records
All hosts with names and IPv6 addresses on the domain, to include websites
Telecommunications Network (Telnet)
Allows a user at one host to establish a virtual connection with another host, and use the remote host as though he/she were typing on its keyboard.
Classless Interdomain Routing (CIDR)
Allows for the more efficient use of IPv4 addressing through a method called subnetting.
Out-of-band Management
Allows management outside of normal communications channels. Also known as lights out management due to having a means to connect to a network device when normal communication channels are down. Uses something physical to manage a device; a cable or a modem.
In-band Management
Allows the management of a network device through the network or within normal communications channels. Using network bandwidth to manage a device.
Variable Length Subnet Masking (VLSM)
Allows us to optimize available IP addresses by specifying a different subnet mask for an IP network, and therefore create subnets of different sizes.
Point-to-Point Protocol (PPP)
Allows users to connect to IP networks using modems or dedicated leased lines. Primarily used to connect users to a LAN. It is relatively slow and though it can connect remote LANs together, the traffic volume should be light.
Flags
An 8 bit field that is utilized to indicate the beginning and the ending of an HDLC Frame.
Name Servers (NSs)
Any other authoritative servers for a zone (other than the SOA). Records stored in these servers are used to resolve names to IP addresses (forward lookups) or IP addresses to names (reverse lookups).
Secure Sockets Layer (SSL)
Application Layer protocol of the TCP/IP suite capable of securing other application layer protocols, most commonly used to ensure the privacy of HTTP transactions. It is limited in the number of applications that it can secure.
Information Frames
Carry the actual data, identified with 00000000
Class A
Class used by IP service providers with 16.7 million available hosts.
Class B
Class used by large corporations with 65,536 available hosts.
Iterative
Client makes additional DNS queries if necessary, in order to find the requested name to IP resolution.
DNS Queries
Client uses a program called a resolver, which knows how to communicate with name servers by sending _____ and listening to responses. Utilizes UDP port 53.
Application Programming Interfaces (APIs)
Code written by programmers that allow an application to call upon other resources, such as those available on a network.
Socket Address
Combination of a communicating IP address and port number.
Dotted Decimal Notation
Common representation of an IP address where each octet is separated from the others by a decimal point. EX: 192.168.0.0
Point to Point (Pt2Pt)
Communications path that is a direct connection between two endpoints. Sometimes called a leased, private, or dedicated line that is reserved 24/7, even when there is no data on it. This is very expensive.
HDLC Frame
Composed of flags (beginning and end), and address field, control field, data field, and Frame Check Sequence (FCS) filed.
Organizationally Unique Identifier (OUI)
Identifier assigned to vendors that is contained in the IEEE OUI database. First half identifies the manufacturer of the NIC. Second half is a number that the manufacturer has not used on a previous NIC.
Reverse Address Resolution Protocol (RARP)
The host knows its physical address but does not have an IP address. Reverse of ARP. This method is not used much anymore.
Application Layer (Layer 7)
The interface between the user's application and the network when the user's network-aware application requires network resources to accomplish a task.
Presentation Layer (Layer 6)
The least used layer due to the standardization of different file types.
Attenuation
The loss of signal intensity over distance
TCP/IP
The most commonly used protocol suite in the networking world that has emerged as the Internet standard. It was created by the DOD in an effort to provide dependable and resilient communications.
tracert
Windows command for traceroute When using traceroute to troubleshoot a network problem by IP address only, use the -d option as it will not resolve IP addresses to host names.
ipconfig
Windows system command used to display IP configurations. Stands for IP configuration.
DHCP Ports
for IPv4 it uses UDP and ports 67 and 68. Client sent packets go to port 68 Server sent packets use port 67 and a destination port of 68.
