DNS Round Robin
DNS Round Robin is used to provide
more than one IP address to a single hostname.
Each IP address represents a
different physical host, and requests will be sent to each of the host in a
rotation order.
Reverse NAME Resolution
Sometimes a computer needs to
convert an IP address to DNS name. This conversion process is known as reverse
name resolution.
The developers of the DNS created a
special domain called in-addr.arpa that is specially designed for reverse name
resolution.
ZONE TYPES
In windows 2003 supports 3
zones
ü Primary zone
ü Secondary zone
ü Stub zone
Primary Zone:
A primary zone contains the master
copy of the zone database. The database is stored in the stored in the Active
Directory database.
Secondary Zone:
A secondary zone a duplicate of a
primary zone on another server contains a backup copy of the primary master
zone database file stored as an identical text file on the local drive. You cannot
modify the resource records in a secondary zone manually you can only update
them by replicating the primary master zone database file using a process
called a zone transfer. You should always create at least one secondary zone
from each file based primary zone in your name space to provide fault tolerance
and load balance the DNS traffic load.
Stub Zone:
A stub zone is a copy of a primary
zone that contains SOA and NS resource records plus the HOST (A) resource
records that identify the authoritative servers for the zone
Using Active Directory
Integrated Zones?
When you are running the DNS server
Service on a computer that is an Active Directory domain controller and you
select the zone in active directory check box when creating a zone using the
new zone wizard the server does not create a zone database file instead it
stores the DNS resource records for the zone in the Active Directory database.
Aging and Scavenging:
The process that can be used by
window server 2003 DNS to clean up the DNS to clean up the DNS database when
resource records no longer required by default it is disabled.
How to verify SRV Records?
Verifying SRV records with
NSLOOKUP.
CMD > NSLOOKUP
LS –T SRV domain
LS –T A Domain
WINS – Windows Internet Name
Service?
It converts NETBIOS name to IP
Addresses.
DNS server converts Host name to IP
address.
NetBIOS name is 16 characters
15 character – system name
1 character – service name (DNS,
DHCP, DC)
Command to check a system’s NetBIOS
Name
Nbtstat – N
Ipconfig –all
WINS server uses LMHOST file which
contains all systems NetBIOS name and its IP addresses.
Path –
C:\windows\system32\drivers\etc\lmhost.sam
When a new system is added in the
network, the LMHost file should be manually updated by the system
administrator. It should be created in all systems.
But DNS server is using Dynamic DNS
method, when a new system is added it will update host name and IP address
automatically.
What is DDNS and why do I need
it?
Dynamic DNS allows servers to
dynamically update and create records in DNS.
NetBIOS name max length?
The NetBIOS naming convention
allows for 16 characters in a NetBIOS name.
Microsoft however limits NetBIOS
names to 15 characters and uses the 16 character as a NetBIOS suffix. The
NetBIOS is used by Microsoft Networking software to identify functionality on
the registered device.
Windows NT is using NetBIOS?
True or false details?
Yes because Microsoft networking
services running on Windows NT –based computer are identified by using NetBIOS
names.
Windows 2000 supports NetBIOS
or not?
Yes using WINS it allows a NetBIOS
name to be converted to an IP address. Therefore computers using WINS must be
using NBT (NetBIOS over TCP/IP). The purpose of WINS is to allow NetBIOS name
to be converted to an IP address. Therefore using wins must be using NBT
(NetBIOS over TCP/IP).
What is a Zone?
Zone is collection of records.
Types of zones
Forward lookup zone (Name to IP)
(A to PTR)
Reverse lookup zone (IP to Name)
(PTR to A)
Zone types
Active directory integrated
Primary zone
(Which store their zone information
in a writable text file on the name Server?)
Secondary zone
(Which store their zone information
in a read-only text file on the name server?)
Is there any option in windows
2000 stub zone?
NO, stub zone is introduced on
windows 2003 server
Net BIOS Name:
The naming mechanism that was used
to refer to a computer or domain in earlier versions of windows. It consists of
a 15-character name and a sixteenth character that references a service. It
usually matches the DNS name.
DNS Records short notes
Host A: A record resolves form a
hostname to IP address.
Pointer (PTR): PTR records resolve
from an IP address to a hostname.
Start of Authority (SOA): SOA
resource record specifies the information required for replication.
Service Record (SRV): A SRV records
resolves from a service name to a hostname and port.
Name Server (NS): NS record
resolves from a domain name to hostname.
Mail Exchange (MX): it indicates
the presence of a SMTP email server.
Your network contains of a
single active directory domain named contoso.com. You have a server named
server1 that runs custom network applications. Server1 has the following IP
address:
192.168.15.10
192.168.15.11
You need to ensure that a client
computer resolves server1.contoso.com to only the 192.168.15.11 IP address.
What should you do from the computer?
Edit the hosts file.
Differences
between the HOSTS and LMHOSTS files in Windows NT.
In Windows NT, the HOSTS file is
for TCP/IP utilities and the LMHOSTS file is for LAN manager NET utilities. If
you cannot ping another computer (using friendly name), check the hosts file.
If you cannot NET VIEW a server using only the tcp/ip protocol, check the
LMHOSTS file.
Hosts file
The hosts file is a common way to
resolve a host name to an ip address through a locally stored text file that
contains ip-address-to-host-name mappings. On most unix-based computers, this
file is /etc/hosts. On windows based computers, this file is the host file in
the systemroot\system32\drivers\etc folder.
The following describes the attributes
of the host file for windows.
1)
A single entry consists of an IP (IPV4 or IPV6) address
and one or more host names.
2)
The hosts file is dynamically loaded into the DNS
client resolver cache, which windows sockets applications use to resolve a host
name to an ip address on both local and remote subnets.
3)
When you create entries in the hosts file and save it,
its contents are automatically loaded into the DNS client resolver cache.
4)
The hosts file can be edited with any text editor.
5)
Each host name is limited to 255 characters
6)
Entries in the hosts file for windows based computers
are not case sensitive.
The advantage of
using a hosts file is that users can customize it for themselves. Each user can
create whatever entries they want, including easy-to-remember nicknames for
frequently access resources. However the individual maintenance required for
the hosts file does not scale well to storing large numbers of FQDN mappings or
reflecting changes to ip address for servers and network resources. The
solution for the large-scale storage and maintenance of FQDN mappings is DNS.
The solution for the maintenance of FQDN mappings for changing IP address is
DNS dynamic update.
Not LMHOSTS file.
The lmhosts file is a local text
file that maps IP addresses to NetBios names of remote servers with which you
want to communicate over the TCP/IP protocol. Windows recognizes names instead
of IP addresses for network requests and name discovery process is used to
correctly route network requests with tcp/ip. Because the name discovery
process is generally not routed by an ip router, the lmhosts file allows
windows machines to communicate using tcp/ip across a subnet.
1)
LMHOSTS contains IP addresses to “NetBIOS over TCP/IP”
name translations.
2)
LMHOSTS is only used by the NBT (NetBIOS over TCP/IP)
interface.
3)
LMHOSTS file contains some valuable additions to the
LAN manager and windows for workgroups LMHOSTS file, such as the ability to
support routed domain logon validation.
4)
LMHOSTS contains static information about TCP/IP
addresses , but using logon scripts and or the replicator service, the “master”
file can be distributed transparently across all stations.
5)
By default the lmhosts file should be located in the
directory %systemroor%\system32\drivers\etc (using c:\winnt\system32\drivers\etc)…
