DNS, DHCP and VPN Borislav Varadinov Telerik Software Academy academy.telerik.com System Administrator

 Domain Name System (DNS)  Dynamic Host Configuration Protocol (DHCP)  Virtual Private Network 2

Domain Name System (DNS)

 DNS is a widely used standardized protocol  A Request for Comments (RFC)-compliant DNS server  Windows Server Role  Used in TCP/IP networks for naming hosts and network services  Locates hosts and services through user-friendly names  Client-Server architecture service  Support for Active Directory integration 4

Local DNS Server Example.com DNS Request Example.com DNS Request Example.com DNS Request News.com DNS Request News.com Root DNS Server.com DNS Server News.com DNS Server

 Forward Lookup Zone  Supports the primary function of DNS, the resolution of host names to IP addresses  Reverse Lookup Zone  Supports the resolution of IP addresses to host names 6

 There are many different types of DNS records  Most common:  A  CNAME  MX  NS  PTR  SOA  SRV 7

 Dynamic update enables DNS client computers to:  Register their resource records  Dynamically update their resource records  Dynamic update is additional DNS standard specification (RFC 2136) 8

9  Primary  Secondary  Stub  Active Directory-Integrated

 Usually DNS Servers store their zones data as text files on the file system  Active Directory–integrated DNS enables to:  Store zone data in AD database  Replicate DNS zone data through AD replication  Secure Dynamic Updates  Allows multimaster writes to zone  Available only on Domain Controllers 10

 A stub zone is a copy of a zone that contains only those resource records that are necessary to identify the authoritative DNS servers for that zone 11

Manageable Name Resolution  Root Hints   Root Hints is a list of IP addresses of DNS servers that are authoritative at the root level of the DNS hierarchy  Forwarders  A forwarder is a DNS server that forwards DNS queries for external names to DNS servers outside that network  Conditional Forwarders  A conditional forwarder is a DNS server that forwards DNS queries according to the DNS domain name in the query 12

 DNS provides the option of dividing up the namespace into one or more zones  DNS delegations can be used to:  Delegate management of part of your DNS namespace to another location or department  Divide large zone into smaller zones to distribute traffic loads among multiple servers   Extend the namespace by adding numerous subdomains 13

 The DNS Services high availability is achieved by using multiple DNS Servers  Use secondary DNS Servers  Use Active Directory-integrated zones  DNS Client chooses primary DNS Server and if it is no available, it asks the next server  In domain infrastructure always put only Domain Controllers for primary and secondary 14

  Provides a mechanism for performing cleanup and removal of stale resource records (RRs)  Aging  Scavenging   DNS server can determine that RRs have aged to the point of becoming stale and remove them from zone data 15

 Round Robin   Used to randomize the results of a similar type of query to provide basic load-balancing functionality  Netmask Ordering   Used to return addresses for type A DNS queries to prioritize local resources to the client  Disable Recursion 16

  DNS Manager (DNSMgmt.msc)   DNSCMD.exe 17

 Install DNS Role  Create new forward and reverse lookup zones  Configure Server and Zone settings  Demonstrate DDNS  Demonstrate Active Directory-Integrated replication  Demonstrate Primary and Secondary DNS Server usage  Demonstrate Forwarders and Conditional Forwarders 18

Dynamic Host Configuration Protocol (DHCP)

 Widely used standardized protocol  Windows Server Role  Client-Server architecture  Integrated with Active Directory and DNS  Authorization  DNS Dynamic Update 20

 DHCP Authorization is a process that:  Register the DHCP Server IP address in Active Directory  Prevent not authorized DHCP Servers to lease IP addresses on the network  Stand-alone DHCP Servers detects if an authorized server is working on the same network segment (Only for Windows Servers) 21

 Install DHCP Server Role  Verify that DHCP Server is authorized 22

 A scope must be properly defined and activated before DHCP clients can use the DHCP server for automatic TCP/IP configuration  A scope has the following properties:  Scope name  Range of possible IP addresses  Unique subnet mask (which determines the network ID for the scope)  Lease duration values 23

 The DHCP options are various configuration settings that are passed to the DHCP Clients  Common DHCP options  DNS Servers  DNS Domain Name  Routers  NTP Servers 24

 You can reserve IP addresses for assignment to specified computers or devices  Reservations ensure that a specified devices always receives the same IP address.  Use reservations for devices that must always have the same IP address:  such as servers that do not support Domain Name System (DNS) dynamic update. 25

 Windows Server 2008 DHCP has both server- side and client-side conflict detection to prevent duplicate IP addresses on your network.  Client conflict detection  Server conflict detection 26

  Relay agent is a service that relays DHCP messages between DHCP clients and DHCP servers on different IP networks 27

 Split Scope  Failover Clustering 28

 Vendor Class  User Class  Ipconfig /setclassid 29

 DHCP MMC Console  Netsh 30

 Install DHCP Role  Create new scope  Configure Server and Scope settings 31

VPN and DirectAccess

 Role Service of Network Access and Policy Services  Provides Routing and NAT functions  Provides Dial-Up and VPN functions 33

34 Internet

 PPTP  L2TP  SSTP  IKEv2 35

 Two NICs  IP Address allocation  Local Administrator 36

  Management software that simplifies and enhances the management of remote connections   Uses profiles made of connection settings that allow connections from the local computer to a remote network   Profiles can be distributed to client computers 37

Network Policy Server (NPS)   Network Policy Server (NPS) can be used as a RADIUS server   Performs (For RADIUS clients):   Authentication   Authorization   Accounting 38

  New remote access feature   Allows connectivity to corporate network   Differs from the traditional VPN connections   Provides support only for domain-joined Windows 7 and above   Enables seamless connectivity to corporate networks 39

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