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HW 8 Prelab
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hw8prelab.md
  1. host is a DNS lookup utility that can be used with a domain name to return a corresponding IP address.

a. The top-level domain is the highest level domain name in a domain name. b. The CNAME is a domain name that is an alias for another domain name. c. A Resolver is another name for the client-side of DNS and is responsible for iniaiting the query to be translated. d. A Name server is another name for the server-side of DNS and is responsible to hosting DNS records and responding to resolvers. e. A label is a part of a DNS domain name that is delimitted by dots. f. A FQDN is the full domain name of a host on the Internet g. BIND is software run on DNS servers that translates domain names to IPs and vice-versa. h. Inverse lookup or reverse lookup is a DNS query that sends an IP address with the aim of receiving the corresponding domain name. i. Resource records are files that represent the structure of the domain name system and are hosted on name servers. j. The start of authority is the root resource record that describes the authoritative information about the DNS zone.

a. An inverse DNS query is another name for a reverse lookup, where a resolver gives a hostname and expects a corresponding IP address. b. An iterative DNS query is a query in which it is the job of the resolver to ask each name server, each of which will return its best answer to the resolver. c. A recursive DNS query is a query where a resolver asks a DNS name server which will process the query and ask other name servers until the RR is found at that point the request loops back through the hierarchy to the original name server and back to the users resolver.

  1. A DNS domain represents a larger organizational namespace (like twitter.com) that can consist of many DNS zones which are smaller subdomains represented by resource records.

  2. Some of the top-level domains in the DNS namespace are .com, .org, .edu, .net, etc.

  3. Domain names are not case sensistive but each dot limited section, has a length limit of 63 characters.

a.root-servers.net	198.41.0.4, 2001:503:ba3e::2:30	VeriSign, Inc.
b.root-servers.net	192.228.79.201, 2001:500:84::b	University of Southern California (ISI)
c.root-servers.net	192.33.4.12, 2001:500:2::c	Cogent Communications
d.root-servers.net	199.7.91.13, 2001:500:2d::d	University of Maryland
e.root-servers.net	192.203.230.10, 2001:500:a8::e	NASA (Ames Research Center)
f.root-servers.net	192.5.5.241, 2001:500:2f::f	Internet Systems Consortium, Inc.
g.root-servers.net	192.112.36.4, 2001:500:12::d0d	US Department of Defense (NIC)
h.root-servers.net	198.97.190.53, 2001:500:1::53	US Army (Research Lab)
i.root-servers.net	192.36.148.17, 2001:7fe::53	Netnod
j.root-servers.net	192.58.128.30, 2001:503:c27::2:30	VeriSign, Inc.
k.root-servers.net	193.0.14.129, 2001:7fd::1	RIPE NCC
l.root-servers.net	199.7.83.42, 2001:500:9f::42	ICANN
m.root-servers.net	202.12.27.33, 2001:dc3::35	WIDE Project

  1. The TLD arpa is used for the "techninal infrastructure" of the Internet, specifically for actions such as reverse IP lookup.

  2. 151.101.21.67 www.cnn.com

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