- a computer uses a CIFS broadcast to get the name of another computer
- organizes computers on a network into groups
- workgroup: a name that organizes a group of computers
- all computers within a domain authenticate to the domain controller when they log in
- Active Directory: an organization of related computers that shares one ore more windows domains
- has no single domain controller
Tuesday, April 30, 2013
Chapter 10: Network Naming Pg 341 - 346
CIFS
Monday, April 29, 2013
Chapter 10: Network Naming pg 326 - 340
Name Servers
- DNS Server: a computer running DNS sever software
- zone: a container for a single domain that gets filled with records
- record: a line in the line zone data that maps an FQDN to an IP address
- systems running DNS server software store the DNS information
- when a system needs to know the IP address for a specifc FQDN, it queries the DNS server listed in the TCP/IP configuration
- Authoritative DNS server: a simple network usually has one DNS server for the entire network
- job is to make sure that all the other name servers are updated for changes
- a DNS server has a signle zone that lists all the host names on the domain and their corresponding IP addresses
- a single DNS domain may have a single authoritative DNS server but a number of other DNS servers
Name Resolution
- a web browser must resolve the name to the web server's IP address to make a connection to that web server
- can be resolved in three ways
- broadcasting
- consulting the locally stored HOSTS text file
- contacting a DNS server
- to broadcast, the host sends a message to all the machines on the network
- works for small networks
- limited because it cannot provide name resolution across routers
- routers do not forward broadcast messages to other networks
- a HOSTS file lists the names and addresses of machines on a network
Monday, April 22, 2013
Network + Practice Exam
Test Taken
Score Given: 6/25
Things To Remember:
Score Given: 6/25
Things To Remember:
- nslooup is used for querying DNS servers to obtain domain name or IP address mapping
- HTTPS uses SSL/TLS on TCP port 443
- In transport mode, IPsec offers encryption.
- TCP port 20 is used for FTP data transfer.
- Coaxial cabling is used with BNC connectors.
- IPv6 addresses consist of 128 bits.
- Layer 2 tunneling Protocol offers no encryptions used with IPsecruns over UDP port 1701
- Network Time Protocol uses UDP port 123
- Smurf attack is an example of a Distributed Denial of Service attack.
- CSMA/CA is the name of an access method used in wireless networks.
- Fake logon screen on a system will most probably be a result of downloading and installing a trojan horse.
- Internet Group Management Protocol is used for establishing multicast group memberships used on IPv4 networks.
- IMAP4 runs on TCP 143 and is used for retrieving e-mail messages from e-mail servers.
- MAC address's consist of 48 bits and is also known as a physical address.
- CSMA/CD is used as an access method used in ethernet networks.
- 802.3ae defines 10 Gigabit Ethernet
Friday, April 19, 2013
Chapter 10: Network Naming pg 317 - 322
How DNS Works
- DNS servers use UDP port 53 and sometimes TCP port 53
- the DNS root for the entire internet consists of 13 powerful DNS server clusters all over the world
-> has the complete definitive name resolution table
- Internet Corporation for Assigned Names and Numbers (ICANN): creates new TLDs
Name Spaces
- Hierarchical Name Space (used by DNS): an imaginary tree structure for possible names that can be used within a single system
-> enables administrators to give networked systems longer names
- Flat Name Space (used by HOSTS): an undivided list containing all names
-> all names must be absolutely unique
- DNS servers use UDP port 53 and sometimes TCP port 53
- the DNS root for the entire internet consists of 13 powerful DNS server clusters all over the world
-> has the complete definitive name resolution table
- Internet Corporation for Assigned Names and Numbers (ICANN): creates new TLDs
Name Spaces
- Hierarchical Name Space (used by DNS): an imaginary tree structure for possible names that can be used within a single system
-> enables administrators to give networked systems longer names
- Flat Name Space (used by HOSTS): an undivided list containing all names
-> all names must be absolutely unique
Chapter 9: TCP/IP Applications Pg 301 - End
Rlogin, RSH, and RCP
- Remote Login (Rlogin): you can connect and run commands by running the program with the host name of the server
-> can configure it to log in automatically without needing to enter a username and password
-> only connects using UNIX hosts
- Remote Shell (RSH): enables you to send single commands to the remote server
-> runs over TCP port 514 by default
- Remote Copy Protocol (RCP): provides the capability to copy files to and from the remote server without needing FTP or NFS
SMTP, POP3, AND IMAP4
- Simple Mail Transfer Protocol (SMTP): used to send e-mail
- Post Office Protocol 3 (POP3): receives e-mail from SMPT using TCP port 110
- Internet Message Access Protocol 4 (IMAP4): retrieves e-mail from an e-mail server
-> enables you to search through your messages on the mail server to find specific keywords
-> supports the concept of folders
File Transfer Protocol (FTP)
- original protocol used on the internet for transferring files
- can transfer while keeping security and data integrity
- uses TCP ports 21 and 20 by default
Things To Remember:
- Remote Login (Rlogin): you can connect and run commands by running the program with the host name of the server
-> can configure it to log in automatically without needing to enter a username and password
-> only connects using UNIX hosts
- Remote Shell (RSH): enables you to send single commands to the remote server
-> runs over TCP port 514 by default
- Remote Copy Protocol (RCP): provides the capability to copy files to and from the remote server without needing FTP or NFS
SMTP, POP3, AND IMAP4
- Simple Mail Transfer Protocol (SMTP): used to send e-mail
- Post Office Protocol 3 (POP3): receives e-mail from SMPT using TCP port 110
- Internet Message Access Protocol 4 (IMAP4): retrieves e-mail from an e-mail server
-> enables you to search through your messages on the mail server to find specific keywords
-> supports the concept of folders
File Transfer Protocol (FTP)
- original protocol used on the internet for transferring files
- can transfer while keeping security and data integrity
- uses TCP ports 21 and 20 by default
Things To Remember:
- Secure Sockets Layer (SSL) is a protocol developed by Netscape for transmitting private documents over the internet. SSL works by using a public key to encrypt sensitive data.
- URLs that use an SSL connection start with HTTPS
- SSH encrypts data and is more secure than Telnet. SSH uses port 22.
- Telnet is used to issue commands to a remote server
Thursday, April 18, 2013
Chapter 9: TCP/IP Applications pg 286 - 300
Connection Status
- open port: a socket that is prepared to respond to any IP Packets destined for that socket's port number
-> every application has an open port
-> to see all listening ports time netstat -an into a command prompt
Rules for Determining Good vs. Bad Communications
- open port: a socket that is prepared to respond to any IP Packets destined for that socket's port number
-> every application has an open port
-> to see all listening ports time netstat -an into a command prompt
Rules for Determining Good vs. Bad Communications
- Memorize known ports for common TCP/IP applications
- Learn netstat such as -an, -n, -o, and -b
- get rid of bad or unnecessary processes
The World Wide Web
- composed of servers that s tore specially formatted documents using Hypertext Markup Language (HTML)
-> many pages now are written using HTML5
- Extensible Markup Language (XML): provides the basic format or language for everything from application programming interfaces to word documents
HTTP
- Hypertext Transfer Protocol (HTTP): underlying protocol used by the web
-> relays commands executed by users without reference to any commands previously executed
Web Servers and Web Clients
- web server: a computer that delivers web pages
-> listen on port 80
- Internet Information Services (IIS): enables you to set a maximum connection limit on your web server based on available bandwidth and memory
- uniform resource locator (URL): complete name of a web server
Secure Sockets layer and HTTPS
- Secure Sockets Layer(SSL): a protocol for transmitting private documents over the internet
- Secure Sockets Layer(SSL): a protocol for transmitting private documents over the internet
- Hypertext Transfer Protocol over SSL (HTTPS)
- Transport Layer Security (TLS)
Wednesday, April 17, 2013
Chapter 9: TCP/IP Applications pg 275 - 286
TCP
- Transmission control Protocol (TCP): enables connection-oriented communication in networks that use the TCP/IP protocol suite
- TCP three-way handshake
- most TCP/IP applications use TCP because connection-oriented sessions are designed to check for errors
DHCP
- Dynamic Host configuration Protocol
- can't assume another computer is ready on either side of the session
- uses port 67 for sending data the the DHCP server
NTP/SNTP
- Network Time Protocol (NTP)
- Simple Network Time Protocol (SNTP)
- synchronize the clocks of devices on the network
TFTP
- Trivial File Transfer Protocol (TFTP): enables you to transfer files from one machine to another
- has no data protection so it is not used for communication between computers across the internet
ICMP
- works at layer 3 to deliver connectionless packets
- handles disconnect messages
IGMP
- Internet Group Management Protocol (IGMP): enables routers to communicate with hosts to determine a "group" membership
Registered Ports
- ports numbers from 1024 to 49151 are called registered ports
- anyone can use these port numbers for their servers
- 0 to 1023: well-known ports
- 1024 to 4951: Registered ports
- 49152 to 65535: dynamic or private ports
- socket: connection data stored on a single computer
- socket pairs: the connection data stored on two computers
- connection: the whole interconnection
- Transmission control Protocol (TCP): enables connection-oriented communication in networks that use the TCP/IP protocol suite
- TCP three-way handshake
- most TCP/IP applications use TCP because connection-oriented sessions are designed to check for errors
DHCP
- Dynamic Host configuration Protocol
- can't assume another computer is ready on either side of the session
- uses port 67 for sending data the the DHCP server
NTP/SNTP
- Network Time Protocol (NTP)
- Simple Network Time Protocol (SNTP)
- synchronize the clocks of devices on the network
TFTP
- Trivial File Transfer Protocol (TFTP): enables you to transfer files from one machine to another
- has no data protection so it is not used for communication between computers across the internet
ICMP
- works at layer 3 to deliver connectionless packets
- handles disconnect messages
IGMP
- Internet Group Management Protocol (IGMP): enables routers to communicate with hosts to determine a "group" membership
Registered Ports
- ports numbers from 1024 to 49151 are called registered ports
- anyone can use these port numbers for their servers
- 0 to 1023: well-known ports
- 1024 to 4951: Registered ports
- 49152 to 65535: dynamic or private ports
- socket: connection data stored on a single computer
- socket pairs: the connection data stored on two computers
- connection: the whole interconnection
Chapter 8: Routing Pg 259 - End
IS-IS
- Intermediate system to Intermediate System (IS-IS): allows you to use a link state dynamic protocol without using OSPF
- uses the concept of areas and send-only updates to routing tables
EIGRP - The Lone Hybrid
- Enhanced Interior Gateway Routing Protocol (EIGRP)
- replaced Interior Gateway Routing Protocol (IGRP)
Set Up of the WAN
- need to know the network IDs for each side of the router
- WAN invariably connects to an ISP
Set Up the LAN
- need to choose a netowrk ID
- need to assign the correct IP information to the LAN-side NIC
Configure A Dynamic Protocol
- dynamic protocols are tied to indiviudal NICs
- make sure the two NICs are configured to use the same dynamic routing protocol
Things To Remember:
- Intermediate system to Intermediate System (IS-IS): allows you to use a link state dynamic protocol without using OSPF
- uses the concept of areas and send-only updates to routing tables
EIGRP - The Lone Hybrid
- Enhanced Interior Gateway Routing Protocol (EIGRP)
- replaced Interior Gateway Routing Protocol (IGRP)
Set Up of the WAN
- need to know the network IDs for each side of the router
- WAN invariably connects to an ISP
Set Up the LAN
- need to choose a netowrk ID
- need to assign the correct IP information to the LAN-side NIC
Configure A Dynamic Protocol
- dynamic protocols are tied to indiviudal NICs
- make sure the two NICs are configured to use the same dynamic routing protocol
Things To Remember:
- A router is a peice of hardware that forwards packets based on IP address
- A router can interconnect different layer 2 technologies
- Port Address Translation enables you to share a single public IP address with many computers
- distance vector routing protocols use hop count to determine the best route.
- OSPF bases routes on speed and sends only route changes to minimize traffic.
- Area 0 is known as the backbone.
- Yost cable was invented to standardize the serial console interface.
Tuesday, April 16, 2013
Chapter 8: Routing Pg 252 - 258
BGP
- autonomous system (AS): one or more networks that are governed by a single dynamic routing protocol within that system
-> do not use IP addresses
-> they use a globally unique Autonomous System Number (ASN)
-> originally 16-bit but are now 32-bit broken into two separate 16-bit numbers broken by a dot (.)
-> AS's communicate using Exterior Gateway Protocol (EGP)
-> networks with an AS communicate using Interior Gateway Protocols (IGP)
- Border Gateway Protocol (BGP - 4): connects all of the Autonomous Systems on the internet
-> BGP routers are manually configured
-> supports policies for limiting which and how other routers may access an ISP
Link State
- link state dynamic routing protocol
-> OSPF
-> IS-IS
OSPF
- Open Shortest Path First (OSPF)
-> used on internal networks
-> converges faster and more efficiently than RIP
-> not often found on home routers
- link state advertisements (LSAs) are sent out by OSPF capable routers
-> forwarded to every OSPF router in the network
- every router in the network is assigned an area ID
- designated router (DR): relays information to all of the other routers in the area
- backdup desginated router (BDR): used in the event the DR is not available
-> the DR and BDR compete to become the DR during the inital LSA packet exchange
- flooding when a new router initially starts and sends out a plethora of LSAs
- cost of an OSPF is based off of 100,000,000/bandwidth in bps
-> the faster the bandwidth the lower the cost
- scales to large networks and is supported by nearly all routers
- OSPF corrects link failures and creates convergence almost immediately
- autonomous system (AS): one or more networks that are governed by a single dynamic routing protocol within that system
-> do not use IP addresses
-> they use a globally unique Autonomous System Number (ASN)
-> originally 16-bit but are now 32-bit broken into two separate 16-bit numbers broken by a dot (.)
-> AS's communicate using Exterior Gateway Protocol (EGP)
-> networks with an AS communicate using Interior Gateway Protocols (IGP)
- Border Gateway Protocol (BGP - 4): connects all of the Autonomous Systems on the internet
-> BGP routers are manually configured
-> supports policies for limiting which and how other routers may access an ISP
Link State
- link state dynamic routing protocol
-> OSPF
-> IS-IS
OSPF
- Open Shortest Path First (OSPF)
-> used on internal networks
-> converges faster and more efficiently than RIP
-> not often found on home routers
- link state advertisements (LSAs) are sent out by OSPF capable routers
-> forwarded to every OSPF router in the network
- every router in the network is assigned an area ID
- designated router (DR): relays information to all of the other routers in the area
- backdup desginated router (BDR): used in the event the DR is not available
-> the DR and BDR compete to become the DR during the inital LSA packet exchange
- flooding when a new router initially starts and sends out a plethora of LSAs
- cost of an OSPF is based off of 100,000,000/bandwidth in bps
-> the faster the bandwidth the lower the cost
- scales to large networks and is supported by nearly all routers
- OSPF corrects link failures and creates convergence almost immediately
Friday, April 12, 2013
Chapter 8: Routing Pg 236 - 252
Network Address Translation
- Network Address Transnation (NAT): hide the IP addresses of computers on the LAN but still enable those computers to communicate with the broader network
The Setup
- requires a block of unique IP addresses
- basic NAT: router replaces the source IP with its outside interface address on outgoing packets
- dynamic NAT: many computers can share a pool of routable IP addresses
Port Address Translation
- Port Address Translation (PAT): uses port numbers to map traffic from specific machines in the network
- when the receiving system sends the packet back it reverses the IP addresses and ports
Port Forwarding
- Static NAT: maps a single routable IP address to a single machine
- port forwarding: can designate a specific local address for various network services
-> computers outside the network can request a service using the public IP address and the port number for the service
-> can be used to hide a service hosted inside a network by changing the default port number
Configuring NAT
- by default, routers are set to Gateway which means NAT is turned on
Dynamic Routing
- routers have static routes
- most routers have the capability to update their routes dynamically
Routing Metrics
- metric: a relative value that routers use when they have more than one route to get to another network
- a router will choose the route with the lowest value IP address
- there is no single rule to set the metric value in a routing table
- Maximum Transmission Unit:
-> determines the largest frame a particular technology can handle
Distance Vector
- Distance Router:
-> calculate the total cost to get to a particular network ID and compare that cost to the total cost of all the other routes
- each distance vector routing protocol has a maximum number of hops that a router will send its routing table to keep traffic down
- convergence (steady state): the updating of the routing tables for all the routers has completed
RIPv1
- Routing Information Protocol(RIP): has a maximum hop count of 15
- variable-length subnet masking (VLSM): networks connected through the router using different subnet masks
RIPv2
- current version of RIP
- VLSM has been added and authentication is built into the protocol
- obsolete for small private WANs that consist of a few routers
- Network Address Transnation (NAT): hide the IP addresses of computers on the LAN but still enable those computers to communicate with the broader network
The Setup
- requires a block of unique IP addresses
- basic NAT: router replaces the source IP with its outside interface address on outgoing packets
- dynamic NAT: many computers can share a pool of routable IP addresses
Port Address Translation
- Port Address Translation (PAT): uses port numbers to map traffic from specific machines in the network
- when the receiving system sends the packet back it reverses the IP addresses and ports
Port Forwarding
- Static NAT: maps a single routable IP address to a single machine
- port forwarding: can designate a specific local address for various network services
-> computers outside the network can request a service using the public IP address and the port number for the service
-> can be used to hide a service hosted inside a network by changing the default port number
Configuring NAT
- by default, routers are set to Gateway which means NAT is turned on
Dynamic Routing
- routers have static routes
- most routers have the capability to update their routes dynamically
Routing Metrics
- metric: a relative value that routers use when they have more than one route to get to another network
- a router will choose the route with the lowest value IP address
- there is no single rule to set the metric value in a routing table
- Maximum Transmission Unit:
-> determines the largest frame a particular technology can handle
Distance Vector
- Distance Router:
-> calculate the total cost to get to a particular network ID and compare that cost to the total cost of all the other routes
- each distance vector routing protocol has a maximum number of hops that a router will send its routing table to keep traffic down
- convergence (steady state): the updating of the routing tables for all the routers has completed
RIPv1
- Routing Information Protocol(RIP): has a maximum hop count of 15
- variable-length subnet masking (VLSM): networks connected through the router using different subnet masks
RIPv2
- current version of RIP
- VLSM has been added and authentication is built into the protocol
- obsolete for small private WANs that consist of a few routers
Thursday, April 11, 2013
Chapter 8: Routing pg 228 - 234
How Routers Work
- router: any piece of hardware that forwards packets based on their destination IP address
- routers work at the Network Layer of the OSI model and the Internet level of the TCP/IP model
- routers are dedicated boxes that contain at least two connections
- router reads the IP addresses of the packets to determine where to send the packets
- routers examine packets and send the packets to the proper destination
Routing Tables
- router inspects each packet's destination IP address and then sends the IP packet out the correct port
- routing table: tells the router exactly where to send the packets
-> each row in a routing table defines a single route
-> each column identifies a specific criteria
-> Destination LAN IP: a defined network ID. Every directly connected network ID is listed here
-> Subnet Mask: needed to define a network ID
- router uses the combination of the destination LAN IP and subnet mask to see if a packet matches the route
-> Gateway: the IP address for the next hop router (where the packet will go next)
-> interface: indicates to the router which port to use
- router compares the destination LAN IP address on each packet toe very listing in the routing table before sending the packet out
- default route tells the router exactly what to do with every incoming packet
- multihomed computers: computers with more than one NIC
- to view routing table type the command: netstat -r
- router: any piece of hardware that forwards packets based on their destination IP address
- routers work at the Network Layer of the OSI model and the Internet level of the TCP/IP model
- routers are dedicated boxes that contain at least two connections
- router reads the IP addresses of the packets to determine where to send the packets
- routers examine packets and send the packets to the proper destination
Routing Tables
- router inspects each packet's destination IP address and then sends the IP packet out the correct port
- routing table: tells the router exactly where to send the packets
-> each row in a routing table defines a single route
-> each column identifies a specific criteria
-> Destination LAN IP: a defined network ID. Every directly connected network ID is listed here
-> Subnet Mask: needed to define a network ID
- router uses the combination of the destination LAN IP and subnet mask to see if a packet matches the route
-> Gateway: the IP address for the next hop router (where the packet will go next)
-> interface: indicates to the router which port to use
- router compares the destination LAN IP address on each packet toe very listing in the routing table before sending the packet out
- default route tells the router exactly what to do with every incoming packet
- multihomed computers: computers with more than one NIC
- to view routing table type the command: netstat -r
Chapter 7: TCP/IP Basics pg 216 - End
Dynamic IP Addressing
- Dynamic Host Configuration Protocol (DCHP)
-> automatically assigns an IP whenever a computer connects to the network
How DHCP Works( Uses ports 67 and 68)
- DHCP Client
- automatically sens out a special DHCP discover packet using the broadcast address
- discover message searches for DHCP servers
- one system on the LAN must be running DHCP server software
- designed to respond to DHCP discover requests
- DHCP server is configured to pass out IP addresses from an IP range (scope)
- DHCP servers can be set up to reserve addresses for specific machines (reservations)
- DHCP client sends out a DHCP request
- DHCP server then sends DHCP acknowledge and lists the MAC address and IP information
- DHCP lease: the acceptance from the DHCP client of the DHCP server's data
-> set for a fixed amount of time (5-8 days)
-> near the end of the lease time, the DHCP client simply makes another DHCP Discover message
- DHCP server looks at the MAC address information and gives the DHCP client the same IP info
Living with DHCP
- biggest issue: a DHCP client tries to get a DHCP address and fails
-> indicated by the operating system posting some form of error and the DHCP client has a strange IP address
- Automatic Private IP Addressing (APIPA) : generates the "special" IP address
-> all DHCP servers generate an APIPA address automatically if they do not recieve a response to a DHCP Discover message
-> DHCP client only generates the last two octets of an APIPA address
-> APIPA cannot issue a default gateway which prevents internet access
-> systems that use static IP addressing can never have DHCP problems
What to Remeber:
- Dynamic Host Configuration Protocol (DCHP)
-> automatically assigns an IP whenever a computer connects to the network
How DHCP Works( Uses ports 67 and 68)
- DHCP Client
- automatically sens out a special DHCP discover packet using the broadcast address
- discover message searches for DHCP servers
- one system on the LAN must be running DHCP server software
- designed to respond to DHCP discover requests
- DHCP server is configured to pass out IP addresses from an IP range (scope)
- DHCP servers can be set up to reserve addresses for specific machines (reservations)
- DHCP client sends out a DHCP request
- DHCP server then sends DHCP acknowledge and lists the MAC address and IP information
- DHCP lease: the acceptance from the DHCP client of the DHCP server's data
-> set for a fixed amount of time (5-8 days)
-> near the end of the lease time, the DHCP client simply makes another DHCP Discover message
- DHCP server looks at the MAC address information and gives the DHCP client the same IP info
Living with DHCP
- biggest issue: a DHCP client tries to get a DHCP address and fails
-> indicated by the operating system posting some form of error and the DHCP client has a strange IP address
- Automatic Private IP Addressing (APIPA) : generates the "special" IP address
-> all DHCP servers generate an APIPA address automatically if they do not recieve a response to a DHCP Discover message
-> DHCP client only generates the last two octets of an APIPA address
-> APIPA cannot issue a default gateway which prevents internet access
-> systems that use static IP addressing can never have DHCP problems
What to Remeber:
- An IPv4 address consists of 32 bits.
- The network ID is the first three octets when using the specified subnet
- A subnet is all 1s followed by 0s
Tuesday, April 9, 2013
Chapter 7: TCP/IP Basics Pg 200 - 216
Class IDs
- Internet Assigned Numbers Authortiy (IANA)
-> formed to track and distribute IP addresses to those who need them
- American Registry for Internet Numbers (ARIN)
-> American region of the IANA
- multicast licenses are used fro one-to-many communciation
- broadcast: every computer on the LAN hears the message
- unicast: one computer on the LAN hears the message
- multicast: multiple computers on the LAN hear the message
CIDR Subnetting
- subnetting: taking a single class of IP addresses and chopping it up into multiple smaller groups
Subnetting
- enables more efficient use of IP addresses
- allows separation of a network for security
- can extend the subnet mask by adding more ones
- never subnet without converting to binary
- has two goals
-> efficiency and making multiple network IDs
Calculating Hosts
- 2^x - 2 = number of hosts
-> x = number of zeros in the subnet mask
Calculating Subnets
- start with a beginning subnet mask and extend the subnet extension as far as you need
- 2^y where y = number of bits you add to the subnet mask
Manual Dotted Decimal to Binary Conversion
- best way to convert is with a calculator
- start with 128 and divide the number in half all the way to 1
- the place the binary numbers under the values from dividing
- then add the decimal values that have a one underneath
- 128 64 32 16 8 4 2 1
1 0 0 1 0 1 1 0
128 + 16 + 4 + 2 = 150
- Internet Assigned Numbers Authortiy (IANA)
-> formed to track and distribute IP addresses to those who need them
- American Registry for Internet Numbers (ARIN)
-> American region of the IANA
- multicast licenses are used fro one-to-many communciation
- broadcast: every computer on the LAN hears the message
- unicast: one computer on the LAN hears the message
- multicast: multiple computers on the LAN hear the message
CIDR Subnetting
- subnetting: taking a single class of IP addresses and chopping it up into multiple smaller groups
Subnetting
- enables more efficient use of IP addresses
- allows separation of a network for security
- can extend the subnet mask by adding more ones
- never subnet without converting to binary
- has two goals
-> efficiency and making multiple network IDs
Calculating Hosts
- 2^x - 2 = number of hosts
-> x = number of zeros in the subnet mask
Calculating Subnets
- start with a beginning subnet mask and extend the subnet extension as far as you need
- 2^y where y = number of bits you add to the subnet mask
Manual Dotted Decimal to Binary Conversion
- best way to convert is with a calculator
- start with 128 and divide the number in half all the way to 1
- the place the binary numbers under the values from dividing
- then add the decimal values that have a one underneath
- 128 64 32 16 8 4 2 1
1 0 0 1 0 1 1 0
128 + 16 + 4 + 2 = 150
Monday, April 8, 2013
Chapter 7: TCP/IP Basics Pg 184 - 198
IP Addresses
- most common IP addresses have a 32-bit value (IPv4)
- 32 binary digits broken into four groups of eight digits
- each 8bit value is converted into a decimal number between 0 and 255
Network IDs
- each computer on a LAN has a very similar IP address
- i.e. only the last number of the IP being unique to each system
Interconnecting
- must have a router to connect to other networks
- most common IP addresses have a 32-bit value (IPv4)
- 32 binary digits broken into four groups of eight digits
- each 8bit value is converted into a decimal number between 0 and 255
Network IDs
- each computer on a LAN has a very similar IP address
- i.e. only the last number of the IP being unique to each system
Interconnecting
- must have a router to connect to other networks
Friday, April 5, 2013
Network+ Chapter 7: TCP/IP Basics pg 177 - 183
The TCP/IP Protocol Suite
- TCP/IP Model: Link, Internet, Transport, and Application layers
Internet Layer Protocols
- takes data chunks from the transport layer, adds an address, and creates the final IP packet
- IP then hands the IP packet to layer 2 for encapsulation into a frame
- ICMP: Internet Control Message Protocol
- full IP packet has 14 different fields
- Transmission Control Protocol (TCP)
- User Datagram Protocol (UDP)
TCP
- 95% of all TCP/IP applications use TCP
- requires both the sending and the receiving machines to acknowledge the other's presence and readiness to send and receive data
- ACK/NACK or just ACK
- chops up data into segments, gives the segments a sequencing number, and verifies that all segments were received
- each application is designed a specific port number
- web servers use port 80 (HTTP)
- e-mail uses port 110 (POP3)
- TCP Headers
- TCP/IP Model: Link, Internet, Transport, and Application layers
Internet Layer Protocols
- takes data chunks from the transport layer, adds an address, and creates the final IP packet
- IP then hands the IP packet to layer 2 for encapsulation into a frame
- ICMP: Internet Control Message Protocol
- full IP packet has 14 different fields
- Version (Ver): defines the type of IP address
- Header Length: total size of the IP portion of the packet in words
- Differentiated Services code Point (DSCP): contains data used by bandwidth sensitive applications
- Time to Live (TTL): prevents an IP packet from indefinitely spinning through the internet
- Protocol: Either TCP or UDP
- Transmission Control Protocol (TCP)
- User Datagram Protocol (UDP)
TCP
- 95% of all TCP/IP applications use TCP
- requires both the sending and the receiving machines to acknowledge the other's presence and readiness to send and receive data
- ACK/NACK or just ACK
- chops up data into segments, gives the segments a sequencing number, and verifies that all segments were received
- each application is designed a specific port number
- web servers use port 80 (HTTP)
- e-mail uses port 110 (POP3)
- TCP Headers
- Sequence Number: used to assemble/disassemble data
- ACK Number: tracks the readiness of the two communicating systems
- Flags: give sending an receiving ends detailed information on state of connection
- Checksum: checks the TCP header for errors
- Source Port
- Destination Port
Chapter 6: Installing a Physical Network pg 170 - End
Cable Testing
- need a midrange tester with TDR
- include the patch cables
Problems in the Telecommunications Room
- keep your diagnostics process documented and organized
- all racks should run off of an interruptible power supply
- all rooms should have temperature monitors
- all rooms should have environmental monitors
Things To Remember From Chapter:
- need a midrange tester with TDR
- include the patch cables
Problems in the Telecommunications Room
- keep your diagnostics process documented and organized
- all racks should run off of an interruptible power supply
- all rooms should have temperature monitors
- all rooms should have environmental monitors
Things To Remember From Chapter:
- Coax cable should not be used in structured cabling networks.
- Bonding, or link aggregation, is the process of using multiple NICs as a single connection, thus increasing speed.
- The CAT 5e rating requires four pairs of wires.
- The patch panel organizes and protects the horizontal cabling in the telecommunications room.
- Patch cables are used to connect the hub to the patch panel and the PCs to the outlet boxes.
- 10BaseT and 100BaseT use UTP cabling in a star topology. 10Base2 is an older, dying technology that doesn't use UTP in a star. Fiber-optic networking uses a star topology, but the name is a dead giveaway hat it doesn't use UTP.
- A tone generator and tone probe work together to enable you to pick a single cable out of a stack of cables.
Thursday, April 4, 2013
The Beginnings of How the Internet Works
So I began the learning process first my replicating the demonstration in the presentation. The idea is to visualize and understand how one machine connects to another. I chose to see the connection between the machine here at the career center and python.org. I began by installing Scapy, and Graph Visualization Tools. I opened Scapy and use the traceroute command to see a list of all the IPs that my machine connects to in order to connect to python.org. I then used a command that would create an visual graph of all the hops the request took to reach python.org
Wednesday, April 3, 2013
Net+ Chapter 6: Installing a Physical Network pg 133 - 169
Patch Panels and Cables
- patch panel
- a bow with a row of female connectors in front and permanent connections in the back
- 110 Block
- UTP cables connect using a punch down tool
- 66 Block
- used more commonly for telephone services but still common to find 66-blocks in a telecommunications room
- patch panels prevent horizontal cabling from being moved
- patch panels are also used to organize cables
- patch panels are available in:
- UTP
- STP
- Fiber Optic
- a mix of the three standards
- UTP patch panels come with ratings
- patch cables:
- short (2-5 foot) UTP cables
- stranded core
Demarc
- physical location of the connection and marks the dividing line of responsibility for the functioning of the network
- NIU:
-> DSL or cable modem supplied by your ISP
Installing Structured Cabling
- get a floor plan
- map the runs of the cables
- find an appropriate room for telecommunications
- short distances from work areas
- has a lot of power sockets
- low humidity
- temperature controls
- not easily accessed
4th Quarter
1. During the 4th quarter, I will learn to properly set up and manage a school tool server for use in Senegal. In addition, I will complete a Python task that is essentially what this woman did.
2. During the 4th quarter, I will make a server for students in Senegal to use. I will also work together with Ben and John to complete a project on understanding how the internet works.
3. I hope to have tested and completed certification in Network+ by May 16th.
2. During the 4th quarter, I will make a server for students in Senegal to use. I will also work together with Ben and John to complete a project on understanding how the internet works.
3. I hope to have tested and completed certification in Network+ by May 16th.
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