Chapter 19: Local Area Networking Flashcards
Protocol Suite/Stack
Combination of protocols together
TCP/IP
Transmission Control Protocol/Internet Protocol
Router
Filters and forwards traffic via IP address
Connects a LAN to the wider internet (or other LANs)
Default Gateway
Router’s LAN IP connection (gateway to the net, essentially)
IP Address
Method for identifying node and network
Written in dotted-decimal notation
IPv4
Internet Protocol version 4
4 sets of 8 binary numbers, 32 bits total
255.255.255.255 is a fully masked IP
Subnet Mask
Blocks out of network ID for IP addresses
255.255.255.0 - all 255 values are locked in as network ID
Remaining set is left for the machines to identify with
IP Conflict
When two hosts have identical IP addresses
IPv6
Internet Protocol version 6
8 groups of 4 hexadecimal characters, 128 bits total (hextets are 16 bits each)
colon separator instead of dotted-decimal
Uses digits and letters up to ffff
leading 0s get dropped, sequential sets of 0s can be replaced with :: (but only once per address)
Public vs Private IP
Public address is like your passport to the internet - used to direct all traffic to you., Public IP address is typically the router’s outward facing address
Private IP address is only for internal network - allows router to distinguish between the different hosts on the network.
Classes of private addresses:
10.0.0.0 - Class A
172.16.0.0 - 172.31.255.255 - Class B
192.168.0.0 - Class C
CIDR
Classless Inter-Domain Routing
Masks using the binary values and “whack” notation
11111111.11111111.11111111.00000000 = /24 network (whack 24).
Remaining 0s are open for host IDs, while 1s are taken up with network ID
IPv6 Construction
Prefix, subnet, interface ID
First three hextets are the prefix (public topology assigned by ISP)
fourth hextet specifies the subnet (private topology)
final four hextets are interface ID (token/host ID)
CIDR notation is used to write the prefixes
link-local address
Automatically assigned to machine when it has not been manually configured or DHCP configured.
Valid only within the private network, routers will not transmit traffic using link-local addresses
IPv4 range: 169.254.0.0/16 (remember 169.254.0.0 and 169.254.255.255 are reserved)
IPv6 range: fe80::/10 (although typically get assigned within the fe80::/64 range)
EUI-64
Extended Unique Identifier
Creates an auto generated IPv6 address for a machine using the MAC address. Means machine will have an address even without DHCP configuration.
Puts MAC in after the IPv6 prefix. 24 bits are the first half of the MAC (with one bit modified from 0 to 1), puts filler 16 bits (FFFF:FFFE), then last 24 bits are the latter half of the MAC address.
DNS and TLD
Domain Name System (converts latin domain names to IP)
Top Level Domains - .com, .edu, .gov, .mil, .int, .net, .org
RS and RA
Router Solicitation and Router Advertisement
RA - provides network ID, subnet, and DNS server
Global Unicast Address
IPv6 equivalent to public address for router
Address Records
A record - IPv4
AAAA record - IPv6
Used by DNS servers to link domain name “blank.com” into an IP address
MX record
Mail Exchange record
Used by DNS servers to direct outgoing email to correct server
DHCP
Dynamic Host Control Protocol
Used to configure hosts, provides IP, DNS server, subnet
Servers have a “pool” or “scope” of IPs to lease out until renewal (can manually drop through a release).
Reservations mean DHCP server always provides same IP to specified host
TXT Records
Spam prevention tools, supposed to make spoofing more difficult
DKIM - Domain Keys Identified Mail
digitally signs mail with a key pulled from the DNS server’s TXT records
SPF - Sender Policy Framework
list of servers that are permitted to send mail from a particular domain
DMARC - Domain-based Message Authentication, Reporting, and Conformance
references DKIM and SPF frameworks, determines what to do with mail that fails these checks
TCP
Transmission Control Protocol - connection-oriented protocol for good order and precise transmission. Makes sure messages are sent and received accurately (no missing packets)
TCP is configured in Start|Settings|Network and Internet|Status
Adapter settings can be cahnged there under Advanced Network Settings
UDP
User Datagram Protocol - connectionless protocol, more like “fire and forget”. Is faster than TCP because it doesn’t require all those same steps
ping
command line, sends frame out to specified location “ping [address/domain]”
-t switch - continuous pinging
-l switch - sets the packet size
ipconfig w/ switches
shows the network settings
ipconfig /all - detailed view
ipconfig /renew - get a new DHCP config
ipconfig /release - dump current DHCP config
ifconfig
Unix version of ipconfig
nslookup/dig
Win/UNIX
gives details on what DNS is giving you
nslookup [address/domain]
tracert/traceroute
Win/UNIX
shows route of packet and time it takes to travel (pathping does the same)
tracert [addres/domain]
3 requirements for network connectivity
1) Connected NIC
2) Proper IP configuration
3) Switch
APIPA
Automatic PRivate IP Addressing
IPv4 range of 169.254.0.1 - 169.254.255.254
Host broadcasts it out, if no other host responds, it self-assigns.
Link Lights
steady on = good signal
flickering/off = bad connection
Activity Lights
Flickers with data transfer
Full-duplex
NIC can send and receive data simultaneously
Autosensing
Switch uses this to detect half vs full duplex devices and therefore how to manage traffic on those lines
Wake-on-LAN
“Magic packet” to turn on a PC through network
Control Panel|Network and Sharing|Manage Network Connections (Rclick) Properties
QoS
Quality of Service - allows networks to prioritize traffic
Unmanaged vs Managed switches
Unmanaged - plug and play, no configuration (good for small networks)
Managed - configuration options, gives switch an IP that can be reached
Workgroup
Allows all systems in shared workgroup to share resources
Typically set fully open, then use NTFS permissions to control read/write capabilities
LDAP
Lightweight Directory Access Protocol
Allows access to network resources through Active Directory verification
Default OUs in AD snapin
Builtin - where built in domain groyups are stored
Computers - all systems stored (servers, devices, workstations)
Domain Controllers - authenticates users
Users - list of users
Users and Computers utility
cleans up account issues, reset passwoerds, enable or disable accounts, etc
Domain Account Powers
1) Logon scripts (map netwrok drives on login, put info box up on login, etc)
2) setup “roaming” profiles (take folders w/ you at each station)
3) “folder redirection” (puts folders on a server instead of locally hosting them)
Steps to map a drive
Right click “This PC” and select map network drive
Select drive you want to map
Set to autoauthenticate or use separate credentials
Troubleshooting Tools
ipconfig - check to see if you are getting an APIPA, that means connection issue with DHCP
check link lights - if they keep going on and off, could be a sign of “port flapping”
Loopback test - test internal NIC circuitry, may need loopback plug to check external port pins
TDR - (Time-domain reflectometer) sends signal that will refelect back if impedence changes, calculates distances to break. Should always include the patch cables in this test
Toner - tone generator and tone probe. Sends signal that the probe will pick up when placed next to cable (like current detector tool)
net
command prompt - view details of a network as well as other tools
net use x: \server1\research = go into server1, find the research folder, map it to drive X:
net view \[NAME] gives available shares and mappings of \[NAME]
