programming4us
programming4us
DESKTOP

Windows Server 2003 : Configuring Advanced DNS Server Properties (part 2)

- Free product key for windows 10
- Free Product Key for Microsoft office 365
- Malwarebytes Premium 3.7.1 Serial Keys (LifeTime) 2019
Simple Example: Local Network Priority

A multihomed computer, server1.lucernepublishing.com, has three A resource records for each of its three IP addresses in the lucernepublishing.com zone. These three records appear in the following order in the zone, either in the zone file or in Active Directory:

server1 IN A 192.168.1.27
server1 IN A 10.0.0.14
server1 IN A 172.16.20.4

When a DNS client resolver at IP address 10.4.3.2 queries the server for the IP addresses of the host server1.lucernepublishing.com, the DNS Server service notes that the originating IP network address (10.0.0.0) of the client matches the network (class A) ID of the 10.0.0.14 address in the answer list of resource records. The DNS Server service then reorders the addresses in the response list, as follows:

server1 IN A 10.0.0.14
server1 IN A 192.168.1.27
server1 IN A 172.16.20.4

If the IP address of the requesting client has no local network match with any of the resource records in the answer list, the list is not prioritized in this manner.

Complex Example: Local Subnet Priority

In a network that uses IP subnetting (nondefault subnet masks), a DNS server first returns any IP addresses that match both the client’s network ID and subnet ID before returning any IP addresses that match only the client’s network ID.

For example, a multihomed computer, server1.lucernepublishing.com, has four A resource records corresponding to each of its four IP addresses in the lucernepublishing.com zone. Two of these IP addresses are for distinct and separate networks. The other two IP addresses share a common IP network address, but because custom netmasks of 255.255.248.0 are used, the IP addresses are located in different subnets. These example resource records appear in the following order in the zone, either in the zone file or in Active Directory:

server1 IN A 192.168.1.27
server1 IN A 172.16.22.4
server1 IN A 10.0.0.14
server1 IN A 172.16.31.5

If the IP address of the requesting client is 172.16.22.8, both IP addresses that match the same IP network as the client, the 172.16.0.0 network, are returned at the top of the response list to the client. However, in this example, the 172.16.22.4 address is placed ahead of the 172.16.31.5 address because it matches the client IP address down through the 172.16.20.0 subnet address.

The reordered answer list returned by the DNS service follows:

server1 IN A 172.16.22.4
server1 IN A 172.16.31.5
server1 IN A 192.168.1.27
server1 IN A 10.0.0.14

Enable Round Robin

The Enable Round Robin option is selected by default. This setting ensures that, in response to a request to resolve the name of a multihomed computer, DNS servers in Windows Server 2003 rotate the order of matching A resource records in the response list returned to subsequent clients. This feature provides a simple way to balance the network load for frequently queried multihomed computers among all the computer’s network adapters. This feature is also commonly used to balance requests between multiple servers that offer identical network services, such as an array of Web servers providing content for a single Web site.

Note

Local subnet priority supersedes the use of round robin rotation for multihomed computers. When enabled, however, round robin is used as a secondary method to sort multiple records returned in a response list.


Round Robin Example

The Web server named server1.lucernepublishing.com has three network adapters and three distinct IP addresses. In the stored zone (either in a database file or in Active Directory), the three A resource records mapping the host name to each of its IP addresses appear in this fixed order:

server1 IN A 10.0.0.1
server1 IN A 10.0.0.2
server1 IN A 10.0.0.3

The first DNS client—Client1—that queries the server to resolve this host’s name receives the list in this default order. However, when a second client—Client2—sends a subsequent query to resolve this name, the list is rotated as follows:

server1 IN A 10.0.0.2
server1 IN A 10.0.0.3
server1 IN A 10.0.0.1

Disabling Round Robin

When you clear the Enable Round Robin check box, round robin is disabled for the DNS server. In this case, when clients query the DNS server to resolve the host name of a multihomed computer, the server always returns the matching A resource records in the order in which those records appear in the zone.

Secure Cache Against Pollution

By default, the Secure Cache Against Pollution option is enabled. This setting allows the DNS server to protect its cache against referrals that are potentially polluting or nonsecure. When the setting is enabled, the server caches only those records with a name that corresponds to the domain for which the original queried name was made. Any referrals received from another DNS server along with a query response are simply discarded.

For example, if a query is originally made for example.microsoft.com, and a referral answer provides a record for a name outside the microsoft.com domain name tree (such as msn.com), that name is discarded if the Secure Cache Against Pollution option is enabled. This setting helps prevent unauthorized computers from impersonating another network server.

When this option is disabled, however, the server caches all the records received in response to DNS queries—even when the records do not correspond to the queried-for domain name.

Name Checking

By default, the Name Checking drop-down list box on the Advanced tab of the DNS server properties dialog box is set to Multibyte (UTF8). Thus, the DNS service by default verifies that all domain names handled by the DNS service conform to the Unicode Transformation Format (UTF). Unicode is a 2-byte encoding scheme, compatible with the traditional 1-byte US-ASCII format, that allows for binary representation of most languages. Each name-checking method is described in Table 2.

Table 2. Name-Checking Methods
MethodDescription
Strict RFC (ANSI)Uses strict checking of names. These restrictions, set in Request for Comments (RFC) 1123, include limiting names to uppercase and lowercase letters (A–Z, a–z), numbers (0–9), and hyphens (-). The first character of the DNS name can be a number.
Non RFC (ANSI)Permits names that are nonstandard and that do not follow RFC 1123 Internet host naming specifications.
Multibyte (UTF8)Permits recognition of characters other than ASCII, including Unicode, which is normally encoded as more than one octet (8 bits) in length.

With this option, multibyte characters can be transformed and represented using UTF-8 support, which is provided with Windows Server 2003.

Names encoded in UTF-8 format must not exceed the size limits clarified in RFC 2181, which specifies a maximum of 63 octets per label and 255 octets per name. Character count is insufficient to determine size because some UTF-8 characters exceed one octet in length. This option allows for domain names using non-English alphabets.
All NamesPermits any naming conventions.

Despite the flexibility of the UTF-8 name-checking method, you should consider changing the Name Checking option to Strict RFC when your DNS servers perform zone transfers to non-Windows servers that are not UTF-8–aware. Although DNS server implementations that are not UTF-8–aware might be able to accept the transfer of a zone containing UTF-8 encoded names, these servers might not be able to write back those names to a zone file or reload those names from a zone file.

You should use the other two Name Checking options, Non RFC and All Names, only when a specific application requires them.

Load Zone Data On Startup

By default, the Load Zone Data On Startup drop-down list box is set to the From Active Directory And Registry option. Thus, by default DNS servers in Windows Server 2003 initialize with the settings specified in the Active Directory database and the server Registry. However, this setting includes two other options, From Registry and From File.

When you configure the Load Zone Data On Startup setting to the From Registry option, the DNS server is initialized by reading parameters stored in the Windows Registry. When you configure this setting to the From File option, the DNS server is initialized by reading parameters stored in a boot file, such as those used by BIND servers.

To use such a file, you should supply a copy of a boot file from a BIND-based DNS server. On BIND-based DNS servers, this file is typically called the Named.boot file. The format of this file must be the older BIND 4 format, not the more recent BIND 8 boot file format. When a boot file is used, settings in the file are applied to the server, overriding the settings stored in the Registry on the DNS server. However, for any parameters not configurable using boot file directives, Registry defaults (or stored reconfigured server settings) are applied by the DNS Server service.

Enable Automatic Scavenging Of Stale Records

By default, the Enable Automatic Scavenging Of Stale Records option is cleared on the Advanced tab. According to this setting, DNS servers in Windows Server 2003 by default do not automatically delete stale or outdated resource records from a zone for which Aging has been enabled.

When this setting is enabled, scavenging of stale resource records is performed automatically at the interval configured in the Scavenging Period.

Other  
  •  Windows 7 : Working with the Multi-Touch User Interface (part 3) - Adding Multi-Touch Interface Functionality
  •  Windows 7 : Working with the Multi-Touch User Interface (part 2) - Obtaining the Multi-Touch Platform Interop Library, Configuring the Application
  •  Windows 7 : Working with the Multi-Touch User Interface (part 1)
  •  Windows Server 2003 : Configuring Zone Properties and Transfers (part 4)
  •  Windows Server 2003 : Configuring Zone Properties and Transfers (part 3)
  •  Windows Server 2003 : Configuring Zone Properties and Transfers (part 2)
  •  Windows Server 2003 : Configuring Zone Properties and Transfers (part 1)
  •  Windows 7 : Managing Pictures with Windows Live Photo Gallery (part 14) - Sharing with E-mail, Sharing on the Web: Services Integration
  •  Windows 7 : Managing Pictures with Windows Live Photo Gallery (part 13) - Printing Pictures and Ordering Prints, Adding Photos to Movies, DVDs, and Data Discs
  •  Windows 7 : Managing Pictures with Windows Live Photo Gallery (part 12) - Using Photos as Slide Shows
  •  
    Top 10
    Free Mobile And Desktop Apps For Accessing Restricted Websites
    MASERATI QUATTROPORTE; DIESEL : Lure of Italian limos
    TOYOTA CAMRY 2; 2.5 : Camry now more comely
    KIA SORENTO 2.2CRDi : Fuel-sipping slugger
    How To Setup, Password Protect & Encrypt Wireless Internet Connection
    Emulate And Run iPad Apps On Windows, Mac OS X & Linux With iPadian
    Backup & Restore Game Progress From Any Game With SaveGameProgress
    Generate A Facebook Timeline Cover Using A Free App
    New App for Women ‘Remix’ Offers Fashion Advice & Style Tips
    SG50 Ferrari F12berlinetta : Prancing Horse for Lion City's 50th
    - Messages forwarded by Outlook rule go nowhere
    - Create and Deploy Windows 7 Image
    - How do I check to see if my exchange 2003 is an open relay? (not using a open relay tester tool online, but on the console)
    - Creating and using an unencrypted cookie in ASP.NET
    - Directories
    - Poor Performance on Sharepoint 2010 Server
    - SBS 2008 ~ The e-mail alias already exists...
    - Public to Private IP - DNS Changes
    - Send Email from Winform application
    - How to create a .mdb file from ms sql server database.......
    programming4us programming4us
    programming4us
     
     
    programming4us