Use ISA/TMG to distribute your custom WPAD configuration file

Use ISA/TMG to distribute your custom WPAD configuration file

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In ISA 2006 SP1 and TMG RTM it’s possible to configure ISA/TMG to distribute
your own custom WPAD configuration file. This can be quite handy if you already
did write your own WPAD configuration file, which had been distributed on a
separate server, or if you want to use the ISA/TMG provided WPAD configuration
file as baseline for some changes, e.g. configure your clients to connect to the
NLB IP instead of using the Client CARP mechanism, which is used by ISA/TMG by
design.

To configure ISA/TMG to use your custom WPAD configuration file, you need to
follow these steps:

1. Please download the compressed file from http://1drv.ms/1qnCmvo

2. Copy & Unzip die File on your ISA/TMG Server.

3. Copy the WPAD configuration file you want to distribute with your ISA/TMG
server to the ISA/TMG local hard drive.

4. Before you proceed importing the WPAD configuration file in your ISA/TMG
configuration, you have to make sure, that there are no non-ASCII Characters in
your WPAD configuration file, as the import process won’t import the complete
file if there are any non-ASCII characters included.

Note: if you use a WPAD configuration file which had been
distributed by ISA 2006, the file will most likely include non-ASCII Characters
at the end of the file.
To remove those characters you have to
delete this part:

function HashString(str, h){
for(var i=0; i<str.length; i++){
var c = str.charAt(i);
if(c
==':' || c == '/') break;
c =
CharToAscii(c.toLowerCase());
h = (h
>>> 4) ^ h_tbl[(h ^ c) & 15];
h = (h >>> 4) ^ h_tbl[(h ^ (c>>>4)) & 15]; h
= MakeInt(h); } return h; }

and replace this part with those lines:

function HashString(str, h){
var hashstr=str.toLowerCase();
for(var i=0; i< hashstr.length; i++){
var c = hashstr.charAt(i);
if(c ==':' || c == '/') break;
c = hashstr.charCodeAt(i);
h
= (h >>> 4) ^ h_tbl[(h ^ c) & 15];
h = (h >>> 4) ^ h_tbl[(h ^ (c>>>4)) & 15]; h
= MakeInt(h); } return h; }

afterwards you have to delete this line:

var Chars ="
!\"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~€???????????Ž????????????ž?
¡¢£¤¥¦§¨©ª«¬¬®¯°±²³´µ¶•¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþ
"; function CharToAscii(c){ return Chars.indexOf(c) + 32; }

5. After you prepared your WPAD configuration file, use the script attached
to import the file to the ISA/TMG configuration, e.g. by executing this command:

to operate on the current array, use '.' as the array name or omit this
option:

cscript kb953293.wsf /array:. /net:internal /script:<FullPathToScript>

For a full list of options please refer to the readme.txt provided in the ZIP
file.

Remark: Please be aware, that any changes you configure in the ISA/TMG
UI will not be applied to the WPAD configuration file after you submit the
custom WPAD configuration file to your configuration. If you want to apply
changes to your WPAD configuration file once you’ve imported it to your
configuration, you have to manually edit the WPAD file and reimport it using the
script again.

If you want to stop using your custom WPAD configuration file and go back
using the ISA/TMG script you have to execute the following command:

cscript kb953293.wsf /array:arrayname /net:internal /del

Hope that helps!

Author

Philipp Sand
Microsoft CSS Forefront Security Edge Team

Technical Reviewer

Frank Heilmann
Microsoft CSS Forefront Security Edge Team

Comments
  • www.isatools.org/.../KB953293.zip does not work :-(

  • we heard from some people, that the downloadlink doesn't work. We're currently working on a solution for this. In the meantime please use jim.isatools.org/.../KB953293.zip

    Thanks

  • I'm just reading up on this stuff - but saw somebody mention that WPAD is outdated and should be avoided. Now a recent post (this one) caters to people having a WPAD config.

    In a plain vanilla environment  I now think one should go with CARP.

    Also - for SharePoint document download it is often suggested to switch off automatic detection in the LAN settings, so that WPAD is taken out of the equation and files load faster. Is there truth to this or could proper WPAD configuration outperformce CARP... or is it more about finegrained control?

    Maybe another blogposting?!? ;-)

  • Hi, Philipp.

    The post mentions ISA 2006 and TMG RTM. Is there any restriction or issue running it on TMG 2010?

    Thanks!

  • Can someone provide an example of changing the wpad file to use the Hardware LB VIP?  We have two TMG servers in an array and want to use a hardware load balancer.  I can't find any documentation on what setting to update to add the LB VIP.

    Thanks!

  • It looks like the link is dead now. Any chance someone still has the file available somewhere?

    Thanks in advance!

  • thanks for the heads up kjs, we will look for a different way to provide the script and will update the article within the next days.
    In the meantime it's always possible to open a support request with Microsoft to provide the script if needed urgently.

  • good News, we found a quick way to publish the script using OneDrive. Please download the script using the new URL from the blog.

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