Network Naming Flashcards
name resolution
process that automatically converts computer names to IP addresses and vice versa
DNS
Domain Name System
powerful, extensible, flexible system that supports name resolution
NetBIOS / NetBEUI
computer boots up
broadcasts its name along with MAC address
every other system heard the message
stored information in its cache
system missing NetBIOS name > broadcast restarts
only applicable on small networks
no actual network sharing done
NetBT
NetBIOS over TCP/IP
TCP ports 137 & 139
UDP ports 137 & 138
used by Windows systems for local network jobs
DNS used for everything else
SMB
Server Message Block
ran on top of NetBT to support sharing of folders and files
not currently dependent on NetBIOS > used NetBIOS names to support sharing & access process
TCP port 445
hosts
special text file used by the original TCP/IP specification for name resolution
hosts file
contained a list of IP addresses for every computer on the Internet
matched to the corresponding system names
saved on every computer
hosts file process
to access another system
looked up the name of that system in the host file
used corresponding address to connect
every OS always looks first the hosts file when attempting to resolve a name
can be manually configuring by editing the text file and saving
DNS servers
special server program that runs DNS
DNS ports
primarily UDP port 53
sometimes TCP 53
DNS root servers
highest servers in the DNS delegation hierachy
13 powerful computers dispersed around the world
have complete definitive name resolution table
most name resolution work is delegated to other DNS servers
Internet name
.
just “dot”
top-level domain servers
just below the DNS root servers in the hierarchy
handle TLD names
TLD names
Top-Level Domain
com, org, net, edu, gov, mil & int
second-level DNS servers
TLD delegate to thousands of second-level servers
handle millions of names i.e. google.com & recreation.gov
DNS example
DNS server controlling hermannpig.com
www 201.28.33.25
computer called www with this IP address
only computer controlling the hermannpig.com domain stores the actual IP address for www.hermannpig.com
DNS servers above this one have a hierarchical system that enables any other computer to find the DNS server that controls the hermannpig.com domain
original TLD names
com org net edu gov mil int
ICANN
Internet Corporation for Assigned Names and Numbers
has authority to add new TLD names
maximum characters for DNS names
255 including separating periods
hierarchical name space
imaginary tree structure of all possible names that could be used within a single system
can name many files / addresses exactly the same as long as they are stored in different locations i.e. Windows file directory
flat name space
large undivided list containing all names with no organization
DNS name space
hierarchy of DNS domains & individual computers names organized into a tree
DNS root
top of DNS tree
holding area to which all domains connect
host names
individual computer names
fit into domains
domains / subdomains
separated by a period
DNS character limitations
uppercase & lowercase letters (does not differentiate)
numbers
hyphens
DNS - Intranets
TCP/IP networks using DNS on small scale
servers aren’t connected to the internet
reading domain names
from left to right
flow from host names to root
brant.domain
FQDN
Fully Qualified Domain Name
complete DNS name - host name and all of its domains in order
when TLD names are required
computers are visible on the internet i.e. com & net
DNS server
computer running DNS server software
zone
container for a single domain that gets filled with records
record
line in the zone data that maps FQDN to IP address
authoritative name server
1 DNS server with single zone
simple networks
powerful servers can host many zones
name server
subordinate DNS servers to support the same domain
single domain - single authoritative domain server
interconnected domain servers (single domain)
every server knows:
name and address of authoritative name server
name and address of every other name server in domain
updating domain DNS servers
add new computers to authoritative name server
authoritative name server automatically distributes information throughout domain
DNS root servers
know and forward requests to authoritative name servers of domain
should be 1 per domain
T/F - Web servers have to be named “www”
False
domain name arrangement
SecondLevel.TopLevel
