dns

Question 1

what is the iterative lookup process

Answer 1

between local dns server and root hints
client requests to resolve domain name
client checks local cache and host file, if info does not exist, forward to local dns server
local dns server checks local cache, if info does not exist, query root hint server
root hint server responds with relevant information about tld and local dns queries the relevant tld
tld responds with relevant information about authoritative name server and local dns queries the relevant name server
authoritative name server responds with the ip address of the queried domain name
local dns server stores the result in local cache
local dns server forwards response back to client

Question 2

what is the recursive lookup process

Answer 2

between client and local dns server
client requests to resolve domain name
client checks local cache and host file, if info does not exist, forward to local dns server
local dns server checks local cache, if info does not exist, forward to forwarder
forwarder checks local cache, if info does not exist, query root hint server
root hint server responds with relevant information about tld and local dns queries the relevant tld
tld responds with relevant information about authoritative name server and local dns queries the relevant name server
authoritative name server responds with the ip address of the queried domain name
forwarder stores the result in local cache
forwarder forwards response back to local dns server
local dns server stores response in local cache
local dns server forwards response back to client

Question 3

what is a stub zone

Answer 3

a stub zone is where a local dns server skips querying root hints server and tld, and goes straight to the authoritative name server of the domain. it is the second fastest way after local cache.

however a stub zone requires the authoritative name server to provide zone transfer privilege to the dns server.

thus should only be applicable to an enterprise that owns multiple domains.

Question 4

benefits on a inhouse forwarder

Answer 4

can perform dns logging and filtering on customised inhouse forwarder

since the forwarder does not contact any external dns servers, it will be safe from any poisoning

inhouse forwarder is faster as it uses recursion

Question 5

bpa 3 levels of severity

Answer 5

error, warning, information

Question 6

what are the guidelines of running bpa

Answer 6

configuration
security
predeployment
postdeployment
performance

Question 7

requirements of bridgehead server

Answer 7

1. have multiple sites
2. each site must have multiple domain controllers
3. these domain controllers must belong to the same domain