Windows Server 2008 R2 Domain Name System Chapter 5

Domain Name System Domain Name System (DNS) Terms DNS and Active Directory DNS components Troubleshooting DNS DNS FAQ

DNS Terms Hostname—name of the computer. No more than 255 characters. Equivalent to the computers first name. PC-001 Host File—text file that lists hostnames to IP addresses C:\windows\system32\drivers\etc Namespace—name of the domain, not specifically and Active Directory Domain. This is equivalent to the computers last name. Abcbusiness.com Fully qualified domain name (FQDN)—first name and last name. PC-001.abcbusiness.com Name server—DNS server that will resolve FQDN’s to IP addresses.

DNS Terms recursion—server directed process to resolve a FQDN. If the server cannot resolve it with it’s own information, it will ask an upstream server. The recursion process starts at the root servers for the.com and works down through the top level domain servers. The process is as follows: 1.Client requests a name like 2.DNS server asks the root servers for the.com domain name servers. 3.Root servers give a list of servers for the.com domain. 4.DNS servers query the.com nam servers for facebook.com 5.It then queries the provided name servers for the FQDN 6.Finally, the DNS server provides the IP address 7.DNS server passes the IP address to the client. 8.The client uses the IP to connect to the web server for

DNS Terms Forwarding—alternative to recursion. Lateral request to another name server within the network. Service resource records (SRVs)—a record within a DNS namespace to resolve a service to a hostname. Essential to Active Directory. Dynamic DNS(DDNS) update—allows DNS client to register their hostnames in an assigned namespace.

DNS Components Fowarders—DNS servers to which the DNS server will refer queries when it cannot resolve them itself. Using forwarders prevents this server from using recursion to resolve DNS queries. You can use forwarders for quicker name resolution. Typically can configure to point to your ISP’s DNS servers.

DNS Components Root Hints—servers to be used for root hints when forwarders are not configured or do not respond. Lists 13 root hint servers on the Internet. You can add your own servers.

DNS Components Forward Lookup Zones—resolves hostnames to IP addresses. Contains the host records for the configured zone. There are three types of zones: Standard Primary  is a text file in which the server maintains the records for a given namespace. Standard Secondary  read-only copy of primary or AD zone. AD Integrated  DNS records are stored in the AD Database and replicated between DC’s, not zone transfers.

DNS Components Reverse Lookup Zone—resolves IP addresses to host names. Also used to provide a level of security with DNS reverse lookups. Reverse lookup not configured properly or DNS setup incomplete DNS is happy

DNS Components Service Resource/Locator Records (SRV)—contains Active Directory related information, such as authentication services. _gc  LDAP service to look up data within the global catalog _kerberos  The authentication process _kpasswd  another part of authentication and password change process _ldap  LDAP service to look up data within the domain

DNS and Active Directory DNS is used to find computers on the Internet A DNS query for returns the IP address of that site. DNS is used to find computers, more specifically, Domain Controllers to locate Active Directory related information. A DNS query for authentication services returns the IP address of the authentication servers. Uses the SRV (service locator records) DNS mirrors the structure of the Active Directory Forest

DNS and Active Directory What happens with Active Directory and DNS The NETLOGON service uses dynamic updates to register SRV and A records in the DNS database Restarting the NETLOGON service when we change our IP addresses or settings updates these records. The SRV record is used to map the name of a service such as LDAP (Lightweight Directory Access Protocol) to a DNS computer name of a server that offers that service. What computer (server) offers that service?

DNS and Active Directory Why does this matter? A domain controller registers it’s DNS name at startup. When a user starts a computer and logs on, the computer queries DNS to find a domain controller within the domain to authenticate to known as the Locator Process 1.The client locator is initiated through RPC to the local Net Logon service. 2.The client collects information that is needed to select a DC and passes the information to the Net Logon service 3.The Net logon service on the client uses the collected information to lookup a domain controller using DsGetDCName.

DNS Troubleshooting Event logging  event log created for the DNS role NSLookup  can query your own server or remotes domain names. Monitoring  Monitoring tab in DNS server properties which allows you to do simple pass/fail tests and recursive tests DNScmd  command-line tool that can perform most tasks in the GUI as well as troubleshooting tasks. Dnscmd /info  configuration of the DNS server Dnscmd /clearcache empties stale, unresolved records Net view  uses netBIOS to retrieve info about a host Nbtstat  uses the netBIOS table to view information about a host or IP address. PING  test connectivity by IP address AND by hostname. Dcdiag  first choice to perform a quick health check on the DNS structure.

DNS FAQ and other Resources US; US; us/library/cc759550(v=WS.10).aspx us/library/cc759550(v=WS.10).aspx