CHAP 7.2 DNS

Question 1

function of domain name solution (DNS)

Answer 1

provides name-resolution service that resolves names to IP addresses

Question 2

dns zones

Answer 2

• forward lookup zone(A): resolve hostname to ip add

- reverse lookup zone(PTR): resolve ip add to hostname

Question 3

dns record types

Answer 3

• SOA: first record in a zone file
• NS: identifies DNS SERVER hosting the zone
• MX: identifies MAIL SERVER for the domain
• SRV: resolves names of servers providing services eg DC
• CNAME: resolves alias to hostname

Question 4

types of dns queries

Answer 4

• recursive query: sent to dns server and requires complete answer
• iterative query: directed to a dns server, may be answered w a referral to another dns server

Question 5

primary zone

Answer 5

• read/write copy of dns database

- records for the namespace are stored in a text

Question 6

secondary zone

Answer 6

• read ONLY copy of database

- records received via zone transfer

Question 7

stub zone

Answer 7

copy of a zone that contains only records used to locate name servers for the domain

Question 8

active directory integrated (zone type)

Answer 8

zone data stored in AD

Question 9

dns zone trfs

Answer 9

• AXFR(full): all records are synchronized

- IXFR(incremental): only new records are synchronized

Question 10

dns caching

Answer 10

• helps to improve efficiency of dns by reducing dns traffic across the internet
• dns server and client will check its dns cache before sending query to other dns servers
• dns query results are stored in memory for a period of time (time-to-live)
• cached info are removed automatically at the end of time-to-live period

Question 11

dns forwarding

Answer 11

• forwarder is a dns server designated to resolve external or offsite dns domain names
• used to forward requests for addresses that are outside the company nwk
• by default, dns servers send queries to Root DNS Server (root hint)

Question 12

root hints

Answer 12

• contains ip addresses for the dns root servers

- when local dns server cant resolve a query using its cache or database, it sends a query to root dns server

Question 13

dns round robin

Answer 13

• responds to dns queries w list of server ip adds hosting the identical services
• essentially just load-balancing and fault-tolerance

Question 14

troubleshooting tools

Answer 14

• NSLOOKUP
• DNS monitoring
• DNSCMD
• DNSLINT