Domain Naming System
2:10 PMWhat is DNS:-
- Domain Name Service/Domain Name System
- Provides resolution of name to IP addressing and resolution of IP addresses to names
- Define a hierarchical namespace where level of the namespace is separated by a “.”
Computer running DNS Service can be:-
DNS Namespace:-
How DNS Queries Work:-
Authoritative & Non-authoritative DNS Server:-
- Return the request IP address
- Return an authoritative “NO”
- Check its cache
- Use forwarders
- Use root hints
- Identifies a host’s name within the DNS namespace hierarchy
- Host name + DNS domain name = FQDN
- Example:
- Then FQDN = sys1.WindowsAdmin.com
Look up Types:-
ZONE:-
- Forward Lookup Zone
- It maintains Host to IP Address Mapping Information
- Reverse Lookup Zone
- It maintains IP Address to host Mapping Information
Types of Records:-
1. SOA Record
- The first in any zone file
2. N S Record
- Identifies the DNS server for each zone
3. Host Record
- Resolves an alias name to a host name
4. Alias Record
- Resolves an alias name to a host name
5. Pointer Record
- Resolves an IP address to a host
6. MX Records
- Used by the mail server
7.SRV Records (Service Records)
- Resolves names of server providing services
Zone Types:-
1. Standard Primary
- It is the Master Copy of all zone information. It is Read/Write copy
2. Standard Secondary
- It is Backup to Primary zone. It
3. Stub Zone
- It contains only NS, SOA & possibly Glue (A) Records with are used to locate name servers
4. Active Directory Integrated
- It stores the information of Zone in ACTIVE DIRECTORY DATABASE
What are Service Records:-
- SRV records allow DNS client to locate TCP/IP-based Services.
- SRV record are used when:
- A client searches Active Directory
- A user attempts to change her password
- An administrator modifies Active Directory
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