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08 - DNS Tutorial Overview.
Testing the new DNS configuration settings in a Windows 7 client computer
Configuring DNS client computers typically entail the execution of the following administrative tasks: 1- Setting the client computer names for each computer. 2- Configure a primary DNS suffix for the computer. 3- Identify the DNS servers for the DNS clients to query for name resolution. You can configure preferred DNS servers, and alternate DNS servers. The alternate DNS servers would be used when the preferred DNS servers are unavailable. 4- Configure a connection specific DNS suffix for every individual adapter on the DNS client.

Troubleshooting the Nslookup "unknown" response for the default DNS server name
Nslookup might also return one of several errors. The following message means that the resolver did not locate a PTR resource record (containing the host name) for the server IP address. Nslookup can still query the DNS server, and the DNS server can still answer queries. 1-error Can't find server name for address < IP Address >: Timed out. 2-error Default servers are not available. 3--error Default Server: Unknown 4-error The following message generally means that the DNS server is running, but is not working properly. < Server > can't find < Name or IP address queried for >: Server failed.

Creating the first DNS forwarder
The order of the IP addresses listed as forwarders on a DNS server determines the sequence in which the IP addresses are used. After the DNS server forwards the query to the forwarder with the first IP address, it waits a short period for an answer from that forwarder (according to the DNS server's time out setting) before resuming the forwarding operation with the next IP address. It continues this process until it receives an affirmative answer from a forwarder. Important: A DNS server cannot forward queries for the domain names in the zones it hosts. When you have configured the other DNS servers in your network to forward queries they cannot resolve locally to that DNS server it will act as your forwarder.


DNS Quiz Questions.

  1. You have two master servers operating in your environment, a primary master and a secondary master. These DNS servers are authoritative for the zone PCTS.com. When the secondary master transfers the domain, what part of the DNS zone does it use to determine if the zone data has changed?

    The TTL, or time to live
    The NS record
    The serial number
    The database record tombstone


  2. This type of DNS query results in the server sending back its best answer from the cache or local data.

    Recursive
    Iterative
    Forward
    NS


  3. You're troubleshooting an error whereby a client computer seems to have old DNS data. You've used ipconfig to see what DNS servers the client is using and you've used ping to verify connectivity to those servers. What command should you use in order to clear the DNS cache on the client so that it will start building a new cache of DNS lookups?

    ipconfig /flushdns
    ipconfig /cleardns
    nslookup /flushdns


  4. Your organization has two DNS servers located at the home office location. However, clients in remote offices are reporting sporadic DNS lookup failures. The network team has informed you that some of the WAN links to the remote offices are nearing saturation. To relieve some of the burden, you decide to implement secondary DNS servers in the remote offices. However, the DNS servers will not be official name servers for the domain, and therefore you don't need to set up NS records for each server. You configure half of the new DNS servers to attempt zone transfer from the primary master and the other half from the secondary master server. After deploying the servers, you notice that none of the servers are able to complete a zone transfer. What is likely the cause of this?

    The primary master server's firewall is not configured for zone transfer data.
    The new DNS servers cannot perform zone transfers from secondary servers.
    The primary server is configured to allow recursive queries only.
    The primary and secondary master servers are not configured to allow zone transfers from the new DNS servers.


  5. The reverse lookup files map IP addresses to host names by using a special domain name that ends in in-addr.arpa and contains the octets of the network portion of the IP address in reverse sequence, such as 0.168.192.in-addr.arpa for the Class C network address range of 192.168.0.0/24. It is a database file that is used for reverse lookups; in other words, a client can provide an IP address and request a matching host name. Pointer (PTR) records are used to provide a static mapping of IP addresses to host names within a reverse-lookup zone. They can be created either manually or automatically when A or AAAA records are added to the forward lookup zone file. Is this statement FALSE, TRUE or POSSIBLE ?





  06 - Creating a new DNS domain - Moving host and pointer records from parent to child DNS domain - Changing the client's default DNS server and IP address - Configuring the client with the new primary DNS suffix


  07 - Setting up the third DNS server computer - Creating a new delegated domain name - Connecting to the 3rd new DNS server from the DNS manager - Adding the third DNS server to the DNS servers list


  08 - Testing the new DNS configuration settings in a Windows 7 client computer - Troubleshooting the Nslookup "unknown" response for the default DNS server name - Creating the first DNS forwarder

08 - DNS Diagram Tutorial


  09 - Configuring the new fourth Caching-only DNS server - Diagram/Explanation to illustrate Caching-only DNS - Connecting to the DNS-CACHE server from the DNS manager - Setting up new IP addresses in the forwarders tab


  10 - Configuring two public DNS and Web server to host a new Website - Diagram/Explanation to illustrate Web Hosting - Creating forward lookup zones for a new master DNS database server







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