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From: Jim Harrison [jim@isatools.org]
Sent: zaterdag 4 september 2004 23:54
To: [ISAserver.org Discussion List]
Subject: [isalist] Windows Update v5 issues and workaround

Importance: High

http://www.ISAserver.org

Hello everyone,

The core cause of this problem is still being worked out, but a clear workaround is available and it boils down to two things:
- Disable authentication for Windows Update requests.
- Disable "global authentication" for web proxy requests

Note: you may have heard that the "ReturnDeniedIfAuthenticated registry setting explained in http://support.microsoft.com/?id=297324
is part of the problem. While applying this setting to ISA 2000 does help expose the WU authentication problems, it is not the cause. If you have applied this setting to your ISA 2000 Server, you did so with good reason to solve a specific problem. You should not remove this setting if you have applied it. By the same token, if you are not experiencing the problem outlined in this KB article, you don't need to and shouldn't apply it. The above article applies only to ISA 2000; you should not apply any ISA 2000 registry settings to ISA 2004 unless the relevant KB article explicitly instructs you to. Currently, none do.

Now let's get on with the workaround.
Per the WU team, there are four destinations that should be included for creating anonymous Windows Update access policies:

TABLE 1
Item FQDN
1 *.download.microsoft.com
2 *.windowsupdate.com
3 *.windowsupdate.microsoft.com
4 windowsupdate.microsoft.com

For ISA 2000
Disable "global" authentication for web proxy requests
1. Open the ISA Manglement MMC
2. Select View, then Advanced
3. Expand Servers and Arrays
4. R-click <ArrayName>, select Properties
5. Select Outgoing Web Requests
6. Uncheck Ask Unauthenticated users for identification
7. Click Apply,
8. When prompted, select Save the changes and restart the service(s)
9. Click OK

Create a destination set for Windows Update domains
1. Expand <ArrayName> and PolicyElements
2. R-click Destination Sets, select New, then Set
3. Enter WindowsUpdate in the Name field, click Next
4. Click Add
5. Enter *.download.microsoft.com in the Domain field
6. Leave the Path field blank
7. Click OK
8. Repeat steps 4 through 7 for each remaining entry in Table 1
9. Click OK

Create an anonymous Site and Content rule for Windows Update requests
1. Expand Access Policy
2. R-click Site and Content Rules, select New, then Rule
3. Enter Windows Update in the Name field, click Next
4. Select Allow, click Next
5. Select Allow access based on destination, click Next
6. In the Apply this rule to: drop-down list, select Specified Destination Set
7. In the Name: drop-down list, select Windows Update
8. Click Next, then Finish

For ISA 2004
Disable "global" authentication for web proxy requests
1. Open the ISA Manglement MMC
2. Expand <ArrayName>, then Configuration
3. Select Networks
4. In the middle pane, select the Networks tab
5. R-click Internal and select Properties
6. Select the Web Proxy tab
7. Click Authentication
8. In the Authentication window, uncheck Require all users to authenticate, click OK
9. Click Apply, then OK
10. Repeat steps 5 through 9 for each network object where you allow Web Proxy requests

Create an anonymous Access Rule for Windows Update
1. In the left pane, R-click Firewall Policy and select New, then Access Rule
2. Enter Windows Update in the Name field, click Next
3. Select Allow, click Next
4. In the This rule applies to: drop-down list, select Selected Protocols
5. Click Add
6. In the Add Protocols dialog, expand Web
7. Select HTTP and click Add
8. Select HTTPS and click Add
9. Click Close, then Next
10. In the Access Rule Sources dialog, click Add
11. In the Add Network Entities dialog, expand Networks
12. Select Internal and click Add
13. For each network where you unchecked Require all users to authenticate, select that network object and click Add
14. Click Close, then Next
15. In the Access Rule Destinations window, click Add
16. In the Add Network Entities window menu bar, click New, then Domain Name Set
17. In the New Domain Name Set Policy Element window, enter Windows Update in the Name field
18. Click New
19. In the Domain names included in this set list, change the new entry to *.download.microsoft.com
20. Repeat steps 19 and 20 for each remaining entry in Table 1
21. Click OK
22. In the New Domain Name Set Policy Element window, select Windows Update, click Add, then Close
23. Click Next, Next, then Finish
24. In the top part of the middle pane, Apply and Discard buttons will appear; click Apply
25. When Apply New Configuration dialog reports "Changes to the configuration were successfully applied", click OK

Make the Windows Update rule the first rule
NOTE: If you prefer to list all of your deny rules first, then you can make the Window Update rule the first rule following them
1. In the left pane, select Firewall Policy
2. If Windows Update is already the first rule in the list, stop here
3. In the middle pane, select Windows Update
4. In the right pane select the Tasks tab
5. Click Move the selected rule up until Windows Update is the first rule in the list
6. In the top part of the middle pane, Apply and Discard buttons should appear; click Apply
7. When Apply New Configuration dialog reports "Changes to the configuration were successfully applied", click OK

Look for a WU KB soon that details the that side of the issue and cross-links to an ISA KB with these instructions.

Jim Harrison
MCP(NT4, W2K), A+, Network+, PCG
http://isaserver.org/Jim_Harrison/
http://isatools.org
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