Server Admin I Unit 5 DNS Flashcards
single-label name
network ID that doesn’t use prefixes or suffixes; commonly the host name
HOSTS File
static file on each Windows based client that is used for DNS name resolution
When to use HOSTS file (4)
- provide single-label name resolution
- map a hostname to an IP address that is different from the one provided by DNS server.
- provide name resolution outside of local subnet without DNS server
Cons to using HOSTS
- requires configuration on each host; impractical outside of small setups
- query will not be sent to DNS server if mapping is in HOSTS file
Link-Local Multicast Name Resolution
LLMNR
Allows clients to find hosts on local suben without DNS or broadcasts
Windows Server 2008 and Vista
What kind of name resolution does LLMNR enable (2)
- hostname to IP address
- IP address to hostname
Where does LLMNR operate on the network
Link local only (local subnet)
When is LLMNR used as a default
When DNS name resolution fails
DNS Suffix Search List
used to locate computers with single label names in a domain other than the one your computer is in.
Where can DNS Suffix Search List be changed. (2)
- Net Adapter properties
- Best changed in DNS Suffix List using Group Policy
DNS Devolution
Active Directory behavior which allows a client computer from a child namespace to access resources in the parent namespace without the need for a fully qualified domain name (FQDN)
How does devolution work
tries to append the parent DNS name as it goes up tree until resolved or until the devolution level is hit
devolution level
specifies the # of labels or size of the parent domain where devolution will stop
ex: westsim.com ( 2 labels) corp.westsim.com (3) labels
Global Names Zone
Zone in DNS db use for single-label name resolution within a domain
When is Global Names Zone used (3)
- allow clients to use simple host names without domain information for name resolution
- allow DNS clients to contact NetBIOS (only hosts without need for a WINS server)
- allow IPv6 only hosts to contact NetBIOS (IPv6 does not support WINS)
New Server 2012 traffic reduction functionalities(2)
- LLMNR outbound queries not sent to mobile broadband & VPN devices
- NetBIOS outbound queries not sent to mobile broadband interfaces
New Server 2012 response time reduction functionalties (2)
- LLMNR & NetBIOS queries sent at same time & optimized for IPv4/6 queries
- LLMNR & NetBIOS queries are sent at same time as DNS queries when a network interface is hijacking DNS names
Domain Name System
DNS
Server is usually used in place of system.
hierarchical distributed db used to translate hostnames to IP address and vice verse
Fully Qualified Domain Name
FQDN
includes hostname and all domains back to root.
root domain (2)
the originating domain in a network indicated by a . (dot) at the end of the FQDN
normally not shown in FQDN
top-level domains
- domain that directly precedes the root domain
- .com, .edu, .gov all are tld examples
second-level domains
- domain that directly precedes the top-level domain
sub level domains
- also called subdomains
- additional domains that directly precede second level or other sub level domains
forward lookup
hostname/FQDN to IP address resolution
reverse lookup
IP address to hostname/FQDN address resolution
authoritative server
DNS server with full complete copy of database for a particular zone
referral
process by which DNS servers querie one another to solve DNS requests
recursion
process a DNS server or host uses root name servers & subsequent servers to perform name resolution
iterative
DNS server requests information from other DNS servers & maintains responsibility for resolution
delegation
DNS server hands responsibility for request to another DNS server