Ziskani IP - vyreseno

Miroslav PRAGL Miroslav.Pragl na Omega-Optix.Cz
Pátek Prosinec 22 11:31:44 CET 2000

omlouvam se, mezitim jsem to nasel:

Automatic Detection of Browser Settings for DHCP and DNS
A DHCP server enables the administrator to centrally specify global and
subnet-specific TCP/IP parameters and to define parameters for clients by
using reserved addresses. When a client computer moves between subnets, it
is automatically reconfigured for TCP/IP when the computer is started.

DNS is a set of protocols and services on a TCP/IP network that allow users
to search for other computers by using hierarchical user-friendly names,
often known as "hosts," instead of numeric IP addresses.

Using DHCP with automatic detection works best for local area network-based
(LAN-based) clients, while DNS enables computers with both LAN-based and
dial-up connections to detect their settings. Although DNS can handle
network and dial-up connections, DHCP provides for faster access to LAN
users and allows greater flexibility in specifying configuration files.

To enable automatic detection of browser settings, you need to configure
specific settings on DNS servers, DHCP servers, or both.

Enabling Automatic Detection of Browser Settings on DHCP
To set up automatic detection of browser settings on a DHCP server, you need
to create a new option type with a code number of 252. Your DHCP server must
support the DHCPINFORM message.

Note Depending on your type of DHCP server, the option names may vary

To add a new DHCP option type
On the DHCP Options menu, click Defaults.
In the Option Class list, click the class for which you want to add a new
option type, and then click New.
In the Name box, type a new option name.
In the Data Type list, click the String data type.
For the default value of the string, type the URL that points to your
configuration file. This file can be a .pac, .jvs, .js, or .ins
configuration file.


In the Identifier box, type the code number 252 to associate with this
option type.
In the Comment box, type a description.
Enabling Automatic Detection on DNS
To enable automatic detection of browser settings on DNS, you need to
configure either the host record or CNAME "alias" record in the DNS database

Host Record
A host record is used to statically associate host (computer) names to IP
addresses within a zone. A host record contains entries for all hosts that
require static mappings, such as work stations, name servers, and mail

The syntax for a host record has this form:

<host name> IN A <ip address of host>

The following list shows some examples.

Host name IN A Host IP address
corserv IN A
nameserver2 IN A
mailserver1 IN A

CNAME Record
These records are sometimes called "aliases" but are technically referred to
as "canonical name" (CNAME) entries. These records allow you to use more
than one name to point to a single host. Using canonical names makes it easy
to do such things as host both an FTP server and a Web server on the same

To configure a DNS database file for automatic detection of browser settings
In the DNS database file, enter a host record named wpad that points to the
IP address of the Web server that contains the .pac, .jvs, .js, or .ins
automatic configuration file.

Enter a CNAME alias named wpad that points to the name (the resolved name,
not the IP address) of the server that contains the .pac, .jvs, .js, or .ins
automatic configuration file.

Note After the record is added and the database file is propagated to the
server, the DNS name wpad.domain.com should resolve to the same computer
name as the server that contains the automatic configuration file.

When using DNS, Internet Explorer constructs a default URL template based on
the host name wpad - for example:


Therefore, on the Web server wpad, you must set up a file or redirection
point named wpad.dat, which delivers the contents of your automatic
configuration file.

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