Ans: DNS is a distributed database system that work at the transport layer to provide name-to-IP address mapping for client applications. DNS also controls email delivery. If your computer cannot access DNS, your web browser will not be able to find web sites, and you will not be able to receive or send email.
Q2. What is the benefits of DNS?
Ans: DNS provides the following benefits:
■ DNS names are user-friendly, which means they are easier to remember than IP addresses.
■ DNS names remain more constant than IP addresses. An IP address for a server can change, but the server name remains the same.
■ DNS allows users to connect to local servers using the same naming convention as the Internet.
Q3. What do you mean by FQDN?
Ans: The FQDN is a DNS name that uniquely identifies the computer on the network. Typically, it is a concatenation of the host name, the primary DNS suffix, and a period. For example, an FQDN might be client1.lucernepublishing.com.
Q4. Describe the DNS components?
Ans: DNS components are following:
DNS Servers: A DNS server is a computer that runs a DNS server program, such as the DNS Server service or Berkeley Internet Name Domain (BIND). .In other words, A server that uses DNS to resolve domain or hostname to IP address.
DNS clients: A DNS client is any machine issuing queries to a DNS server. The client hostname may or may not be registered in a name server (DNS) database. Clients issue DNS requests through processors called resolvers.
DNS Resolvers: A DNS resolver is a service that uses the DNS protocol to query for information from DNS servers. DNS resolvers communicate with either remote DNS servers or the DNS server program running on the local computer. In Windows Server 2003, the function of the DNS resolver is performed by the DNS Client service. Besides acting as a DNS resolver, the DNS Client service provides the added function of caching DNS mappings.
Resource Records: Resource records are DNS database entries that are used to answer DNS client queries. Each DNS server contains the resource records it needs to answer queries for its portion of the DNS namespace. Resource records are each described as a specific record type, such as host address (A), alias (CNAME), and mail exchanger (MX).
Root Server: The root server is the server whose zone consists of the complete tree. Basically a root server does not keep information about domain names but actually delegates its own authority to other server. At present, there are 13 root servers distributed all over the world, which are able to cover the entire set of domain names.
Q5. What is a Name Server?
Ans: Name server is a server program that holds a master or a copy of a name-to-address mapping database.
Q6. What is a Primary DNS Server?
Ans: A primary DNS server is the “owner” of the zones defined in the database. The primary DNS server has the authority to make changes to the zones it owns.
Q7. What is Secondary DNS Server?
Ans: Secondary DNS server receive the read only copy of zones through zone transfer. The secondary DNS server can resolve queries from this read-only copy but cannot make changes or updates. A single DNS server may contain multiple primary and secondary DNS zones.
Q8. What is Domain Namespace?
Ans: The domain namespace is a hierarchical, tree-structured namespace, starting at an unnamed root used for all DNS operations. In the DNS namespace, each node and leaf in the domain namespace tree represents a named domain. Each domain can have additional child domains. The maximum levels of the tree are 128 and each level of the tree can have a string of 63 characters. The root of the DNS hierarchy is represented by period “.”.
Ans: The domains directly below the root are called top-level domains (TLDs).There are three categories of TLDs:
•ARPA: This is a special domain—it is only used today for reverse-name lookups.
•Two-letter country-based domain names: These country code domains are based on the International Organization for Standardization (ISO) country name, and are used principally by companies and organizations outside the United States. The exception is the United Kingdom, which uses .uk as the TLD, even though its ISO country code is GB.
Q10. Define the DNS Zone?
Ans: A zone represents a discrete portion of the domain namespace. Zones provide a way to partition the domain namespace into manageable sections, and they provide the following functions:
(i)Multiple zones in a domain namespace are used to distribute administrative tasks to different groups.
(ii)A zone must encompass a contiguous domain namespace.
Zones always consist of entire domains or subdomains.
Q11. Describe the different kinds of DNS zones?
Ans:
Primary zone: A primary zone contains the master copy of the zone database, where administrators make all changes to the zone’s resource records, is in the primary zone.
Secondary Zone: The secondary zone contains a backup copy of the primary master zone database file, stored as an identical text file on the server’s 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.
Stub zone A copy of a primary zone that contains Start Of Authority (SOA) and Name Server (NS) resource records, plus the Host (A) resource records that identify the authoritative servers for the zone, the stub zone forwards or refers requests. When you create a stub zone, you configure it with the IP address of the server that hosts the zone from which you created the stub. When the server hosting the stub zone receives a query for a name in that zone, it either forwards the request to the host of the zone or replies with a referral to that host, depending on whether the query is recursive or iterative.
Active Directory Zone: Using an Active Directory–integrated zone increases fault tolerance and (by default) turns every domain controller in the domain running a DNS server into a primary server. To configure a primary zone as an Active Directory–integrated zone, the original DNS server on which the zone is created must be an Active Directory domain controller.
Q12. What is the resource record?
Ans: Resource Records (RRs) are the DNS data records. Resource record contains the information about some resource on the network, such as its IP address. Resource records are the data elements that define the structure and content of the domain name space. All DNS operations are ultimately formulated in terms of resource records.
Q13. DNS record types- describe the most important ones.
Ans: DNS records are the following types:
Host Record(A): The A record specifies the IP address of this host. A records are used to resolve a query for the IP address of a specific domain name. This record type is defined in RFC 1035.
Alias Record(CNAME): The CNAME record specifies the actual domain name of this object. When DNS queries an aliased name and finds a CNAME record pointing to the canonical name, it then queries that canonical domain name. This record type is defined in RFC 1035.
Mail Exchanger records(MX): The MX records defines a mail exchanger host for mail sent to this domain. These records are used by SMTP (Simple Mail Transfer Protocol) to locate hosts that will process or forward mail for this domain, along with preference values for each mail exchanger host. Each mail exchanger host must have a corresponding host address (A) records in a valid zone. This record type is defined in RFC 1035.
Reverse-lookup Pointer records(PTR): The PTR record specifies the domain name of a host for which you want a PTR record defined. PTR records allow a host name lookup, given an IP address. This record type is defined in RFC 1035.
Start of Authority records(SOA): The SOA record specifies that this server is authoritative for this zone. An authoritative server is the best source for data within a zone. The SOA record contains general information about the zone and reload rules for secondary servers. There can be only one SOA record per zone. This record type is defined in RFC 1035.
Q14. What is DDNS and why do I need it?
Ans: Dynamic DNS (described in RFC 2136) allows servers to dynamically update and create records in DNS. Dynamic DNS is used by the Exchange server to create server records and other entries used by the Exchange Servers for things like message routing. In a simple Exchange organization, DDNS is not strictly necessary, but makes administration much easier.
Q15. How will you register and activate windows?
Ans: If you have not activated windows XP, you can do so at any time by clicking the windows Activation icon in the system tray to initiate activation. Once you have activated windows XP, this icon disappears from the system tray. For registration Start ==> Run ==> regwiz /r
Q16. Discribe the importance of DNS to AD?
Ans:
Q17. Write down the DNS troubleshooting tools?
Ans: DNS troubleshooting tools are:
Nslookup
Ipconfig
Dnscmd
Q18. What is nslookup utility?
Ans: Nslookup utility is a troubleshooting tool of DNS. Nslookup is a standard command-line tool provided in most DNS server implementations, including Windows Server 2003. You can do a number of useful things with nslookup:
Use it in noninteractive mode to look up a single piece of data.
Enter interactive mode and use the debug feature
Perform the following from within interactive mode:
· Set options for your query
· Look up a name
· Look up records in a zone
· Perform zone transfer
· Exit nslookup
Q19. How to determine whether there is an issue with the DNS configuration of your connection to your ISP?
Ans: At a command prompt, type ipconfig /all, and then press ENTER to display the IP address of your DNS server. If the IP address for your DNS server does not appear, you need contact your ISP.
Q20. What is DNS Forwarder?
Ans:
Q21. Which command will you use to find out the name of the pc in networks?
Ans:
NSLOOKUP[192.168.0.1] [Ip of target computer]
Q22. What protocol is used by DNS name servers?
Ans: DNS uses UDP for communication between servers. It is a better choice than TCP because of the improved speed a connectionless protocol offers. Of course, transmission reliability suffers with UDP.
Q23. What is the “in-addr.arpa” zone used for?
Ans:
Q24. What are the requirements from DNS to support AD?
Ans:
Q25. How do you manually create SRV records in DNS?
Ans: this is on windows server go to run ---> dnsmgmt.msc rightclick on the zone you want to add srv record to and choose "other new record" and choose service location(srv).....
Q26. Name 3 benefits of using AD-integrated zones?
Ans:
1. you can give easy name resolution to ur clients.
2. By creating AD- integrated zone you can also trace hacker and spammer by creating reverse zone.
3. AD integrated zoned all for incremental zone transfers which on transfer changes and not the entire zone. This reduces zone transfer traffic.
4. AD Integrated zones suport both secure and dmanic updates.
5. AD integrated zones are stored as part of the active directory and support domain-wide or forest-wide replication through application pertitions in AD.
Q27. What are the benefits of using Windows 2003 DNS when using AD-integrated zones?
Ans: DNS supports Dynamic registration of SRV records registered by a Active Directory server or a domain controller during promotion. With the help of SRV records client machines can find domain controllers in the network.
1. DNS supports Secure Dynamic updates. Unauthorized access is denied.
2. Exchange server needs internal DNS or AD DNS to locate Global Catalog servers.
3. Active Directory Integrated Zone. If you have more than one domain controller (recommended) you need not worry about zone replication. Active Directory replication will take care of DNS zone replication also.
4. If your network use DHCP with Active Directory then no other DHCP will be able to service client requests coming from different network. It is because DHCP server is authorized in AD and will be the only server to participate on network to provide IP Address information to client machines.
5. Moreover, you can use NT4 DNS with Service Pack 4 or later. It supports both SRV record registration and Dynamic Updates.
Using Microsoft DNS gives the following benefits: If you implement networks that require secure updates. If you want to take benefit of Active Directory replication. If you want to integrate DHCP with DNS for Low-level clients to register their Host records in Zone database.
Q28. You installed a new AD domain and the new (and first) DC has not registered its SRV records in DNS. Name a few possible causes.
Ans: The machine cannot be configured with DNS client her own The DNS service cannot be run
Q27. What are the benefits and scenarios of using stub zones?
Ans: One of the new features introduced in the Windows Server 2003-based implementation of DNS are stub zones. Its main purpose is to provide name resolution in domains, for which a local DNS server is not authoritative. The stub zone contains only a few records: - Start of Authority (SOA) record pointing to a remote DNS server that is considered to be the best source of information about the target DNS domain, - one or more Name Server (NS) records (including the entry associated with the SOA record), which are authoritative for the DNS domain represented by the stub zone, - corresponding A records for each of the NS entries (providing IP addresses of the servers). While you can also provide name resolution for a remote domain by either creating a secondary zone (which was a common approach in Windows Server 2000 DNS implementation) or delegation (when dealing with a contiguous namespace), such approach forces periodic zone transfers, which are not needed when stub zones are used. Necessity to traverse network in order to obtain individual records hosted on the remote Name Servers is mitigated to some extent by caching process, which keeps them on the local server for the duration of their Time-to-Live (TTL) parameter. In addition, records residing in a stub zone are periodically validated and refreshed in order to avoid lame delegations.
Q28. What are the benefits and scenarios of using Conditional forwarding?
Ans: The benefits are speed up name resolution in certain scenarios. According to research that is forwarded to the correct server or with specific speed. And down where DNS queries are sent in specific areas.
Q29. What are the difference between Windows Clustering, Network Load Balancing and Round Robin, and scenarios for each one?
Ans:
Q30. How do I work with the host name cache on a client computer?
Ans:
Q31. How do I clear the DNS cache on the DNS server?
Ans: To clear DNS Cache do the following:
1. Start
2. Run
3. Type "cmd" and press enter
4. In the command window type "ipconfig /flushdns"
5. If done correctly it should say "Successfully flushed the DNS Resolver Cache."
Q32. What is the 224.0.1.24 address used for?
Ans:
Q33. What is WINS and when do we use it?
Ans: Windows Internet Name Service (WINS) provides a dynamic replicated database service that can register and resolve NetBIOS names to IP addresses used on your network. The Microsoft® Windows Server 2003 family provides WINS, which enables the server computer to act as a NetBIOS name server and register and resolve names for WINS-enabled client computers on your network as described in the NetBIOS over TCP/IP standards
Q34. What is components of WINS?
Ans: WINS components are the following:
WINS Server
WINS clients
WINS database
WINS proxis
http://technet.microsoft.com/en-us/library/cc781189(WS.10).aspx
Q35. What is the role of WINS in the network?
Ans: Role of WINS in the Network
Although NetBIOS and NetBIOS names can be used with network protocols other than TCP/IP, WINS was designed specifically to support NetBIOS over TCP/IP (NetBT). WINS is required for any environment in which users access resources that have NetBIOS names. If you do not use WINS in such a network, you cannot connect to a remote network resource by using its NetBIOS name unless you use Lmhosts files, and you might be unable to establish file and print sharing connections.
The following figure illustrates the role of WINS for computers that use NetBIOS names. Typically, DHCP is used to assign IP addresses automatically.
WINS Name Registration and Resolution
In a typical scenario, the following occurs:
ClientA, which uses NetBIOS and is a WINS client, sends a name registration request to its configured primary WINS server (WINSA) when it starts up and joins the network. WINSA adds ClientA's NetBIOS name and IP address to the WINS database.
When ClientB needs to connect to ClientA by its name, it requests the IP address from the WINS server.
The WINS server locates the corresponding entry in its database and replies with ClientA's IP address.
Q36. What is benefits of WINS?
Ans: WINS provides the following benefits over other NetBIOS name resolution methods:
WINS name resolution reduces NetBIOS name query broadcast traffic because clients can query a WINS server directly instead of broadcasting queries.
WINS enables the Computer Browser service to collect and distribute browse lists across IP routers.
The WINS dynamic name-to-address database supports NetBIOS name registration and resolution in environments where DHCP-enabled clients are configured for dynamic TCP/IP address allocation.
The WINS database also supports centralized management and replicates name-to-address mappings to other WINS servers.
WINS and DNS can be used in the same environment to provide combined name searches in both namespaces.
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