DNS Flashcards
What is a DNS?
Domain Name Service is a service that is used by the TCP/IP Network that translates domains to IP addresses
What port does DNS use?
port 53
Primary zone
read/write copy of the DNS database
easy to recover
must exist to make changes
Secondary zone
Read only copy of the DNS Database
Useful for load balancing
a windows secondary zone can be used for a primary unix zone
Stub zone
a copy of a zone that only locates servers (redirects requests to servers that can answer it)
subset of records = Glue host (A), Start of Authority (SOA), Name Server (NS)
Can use as forwarder
AD integrate zone
zone data is stored in ADDS instead rather than zone files
only available to domain controllers
high availability and redundancy
Host Records
A and AAAA (ipv4 and ipv6), identify hostname to ip address and vice versa
Mail Exchanger record (MX)
Identifies Mail server for DNS name
Service Record (SRV)
Locates services on a network
contains following data (Service, Target Port, Priority)
Service <–> Hostname
Name Server (NS) records
contains authoritative DNS servers for the domain
Alias (CNAME) records
alternative record for another record
Start of Authority (SOA) record
Only one per zone
primary name server
contains email of admin
serial number
refresh time
Pointer
maps ip address to domain
Forwarder
Can be used to forward request to a specific ip address rather than having to search through DNS servers, it is much more efficient because of that. It is also useful if the domain you’re looking for is not a qualified domain
DNSSEC
provides DNS resolvers or clients with proof of DNS records or verifiable denial of existence
DNS socket pool
Randomly uses a different port from a pool so attacker can’t guess where the request is coming from
Difference between resolver and conditional resolver?
forwarder forwards requests that cannot be resolved on local DNS to a specific DNS server, while conditional forwarder sends specific requests to speecific servers
