>What is the main purpose of a DNS server? DNS servers are used to resolve FQDN hostnames into IP addresses and vice versa. >What is the port no of dns ? 53. >What is a Forward Lookup? Resolving Host Names to IP Addresses. >What is Reverse Lookup? It?s a file contains host names to IP mapping information. >What is a Resource Record? It is a record provides the information about the resources available in the N/W infrastructure. >What are the diff. DNS Roles? Standard Primary, Standard Secondary, & AD Integrated. >What is a Zone? Zone is a sub tree of DNS database. >Secure services in your network require reverse name resolution to make it more difficult to launch successful attacks against the services. To set this up, you configure a reverse lookup zone and proceed to add records. Which record types do you need to create? PTR Records >SOA records must be included in every zone. What are they used for ? SOA records contain a TTL value, used by default in all resource records in the zone. SOA records contain the e-mail address of the person who is responsible for maintaining the zone. SOA records contain the current serial number of the zone, which is used in zone transfers. >By default, if the name is not found in the cache or local hosts file, what is the first step the client takes to resolve the FQDN name into an IP address ? Performs a recursive search through the primary DNS server based on the network interface configuration . > What is primary, Secondary, stub & AD Integrated Zone? Primary Zone: - zone which is saved as normal text file with filename (.dns) in DBS folder. Maintains a read, write copy of zone database. Secondary Zone: - maintains a read only copy of zone database on another DNS server. Provides fault tolerance and load balancing by acting as backup server to primary server. Stub zone: - contains a copy of name server and SOA records used for reducing the DNS search orders. Provides fault tolerance and load balancing. > How do you manually create SRV records in DNS? 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). > What is the main purpose of SRV records ? SRV records are used in locating hosts that provide certain network services. > Before installing your first domain controller in the network, you installed a DNS server and created a zone, naming it as you would name your AD domain. However, after the installation of the domain controller, you are unable to locate infrastructure SRV records anywhere in the zone. What is the most likely cause of this failure ? The zone you created was not configured to allow dynamic updates. The local interface on the DNS server was not configured to allow dynamic updates. > Which of the following conditions must be satisfied to configure dynamic DNS updates for legacy clients ? The zone to be used for dynamic updates must be configured to allow dynamic updates. The DHCP server must support, and be configured to allow, dynamic updates for legacy clients. > At some point during the name resolution process, the requesting party received authoritative reply. Which further actions are likely to be taken after this reply ? After receiving the authoritative reply, the resolution process is effectively over. > Name 3 benefits of using AD-integrated zones. Active Directory integrated DNS enables Active Directory storage and replication of DNS zone databases. Windows 2000 DNS server, the DNS server that is included with Windows 2000 Server, accommodates storing zone data in Active Directory. When you configure a computer as a DNS server, zones are usually stored as text files on name servers that is, all of the zones required by DNS are stored in a text file on the server computer. These text files must be synchronized among DNS name servers by using a system that requires a separate replication topology and schedule called a zone transfer However, if you use Active Directory integrated DNS when you configure a domain controller as a DNS name server, zone data is stored as an Active Directory object and is replicated as part of domain replication. > Your company uses ten domain controllers, three of which are also used as DNS servers. You have one companywide AD-integrated zone, which contains several thousand resource records. This zone also allows dynamic updates, and it is critical to keep this zone up-to-date. Replication between domain controllers takes up a significant amount of bandwidth. You are looking to cut bandwidth usage for the purpose of replication. What should you do? Change the replication scope to all DNS servers in the domain. >You are administering a network connected to the Internet. Your users complain that everything is slow. Preliminary research of the problem indicates that it takes a considerable amount of time to resolve names of resources on the Internet. What is the most likely reason for this? DNS servers are not caching replies.. Local client computers are not caching replies… The cache.dns file may have been corrupted on the server. >What are the benefits of using Windows 2003 DNS when using AD- integrated zones? If your DNS topology includes Active Directory, use Active Directory integrated zones. Active Directory integrated zones enable you to store zone data in the Active Directory database.Zone information about any primary DNS server within an Active Directory integrated zone is always replicated. Because DNS replication is single-master, a primary DNS server in a standard primary DNS zone can be a single point of failure. In an Active Directory integrated zone, a primary DNS server cannot be a single point of failure because Active Directory uses multimaster replication. Updates that are made to any domain controller are replicated to all domain controllers and the zone information about any primary DNS server within an Active Directory integrated zone is always replicated. Active Directory integrated zones: Enable you to secure zones by using secure dynamic update. Provide increased fault tolerance. Every Active Directory integrated zone can be replicated to all domain controllers within the Active Directory domain or forest. All DNS servers running on these domain controllers can act as primary servers for the zone and accept dynamic updates. Enable replication that propagates changed data only, compresses replicated data, and reduces network traffic. If you have an Active Directory infrastructure, you can only use Active Directory integrated zones on Active Directory domain controllers.If you are using Active Directory integrated zones, you must decide whether or not to store Active Directory integrated zones in the application directory partition. You can combine Active Directory integrated zones and file-based zones in the same design. For example, if the DNS server that is authoritative for the private root zone is running on an operating system other than Windows Server 2003 or Windows 2000, it cannot act as an Active Directory domain controller. Therefore, you must use file-based zones on that server. However, you can delegate this zone to any domain controller running either Windows Server 2003 or Windows 2000. >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. The machine cannot be configured with DNS client her own . The DNS service cannot be run. >What are the benefits and scenarios of using Stub zones? Understanding stub zones A stub zone is a copy of a zone that contains only those resource records necessary to identify the authoritative Domain Name System (DNS) servers for that zone. A stub zone is used to resolve names between separate DNS namespaces. This type of resolution may be necessary when a corporate merger requires that the DNS servers for two separate DNS namespaces resolve names for clients in both namespaces. A stub zone consists of: ? The start of authority (SOA) resource record, name server (NS) resource records, and the glue A resource records for the delegated zone. The IP address of one or more master servers that can be used to update the stub zone. The master servers for a stub zone are one or more DNS servers authoritative for the child zone, usually the DNS server hosting the primary zone for the delegated domain name. Use stub zones to: ? Keep delegated zone information current. By updating a stub zone for one of its child zones regularly, the DNS server hosting both the parent zone and the stub zone will maintain a current list of authoritative DNS servers for the child zone. ? Improve name resolution. Stub zones enable a DNS server to perform recursion using the stub zone's list of name servers without needing to query the Internet or internal root server for the DNS namespace. ? Simplify DNS administration. By using stub zones throughout your DNS infrastructure, you can distribute a list of the authoritative DNS servers for a zone without using secondary zones. However, stub zones do not serve the same purpose as secondary zones and are not an alternative when considering redundancy and load sharing. There are two lists of DNS servers involved in the loading and maintenance of a stub zone: ? The list of master servers from which the DNS server loads and updates a stub zone. A master server may be a primary or secondary DNS server for the zone. In both cases, it will have a complete list of the DNS servers for the zone. ? The list of the authoritative DNS servers for a zone. This list is contained in the stub zone using name server (NS) resource records.