Tag Archive for 'firewall'

ActiveSync Random Password Prompts Fixed

Published by Bret Fisher on Oct 1, 2009 in Microsoft, Networking and Security, Solution Writeups and Tech. 3 Comments Tags: , , , , , , , .

They were getting random prompts for passwords in ActiveSync on Windows Mobile 6.0 and 6.1.  They had Exchange 2007, and ISA Server 2006, but this problem showed up months after Exchange was migrated to 2007.  It seemed random.  The error on ActiveSync was the generic:

please log in access was denied 0×85010002

In the ISA Monitoring you would see a denied connection on your ActiveSync rule with this status:

12239 The server requires authorization to fulfill the request. Access to the Web server is denied. Contact the server administrator.

I tested with Windows Mobile Emulator from outside the firewall and was able to reproduce the error within hours (just letting it sit there).

I first thought this was the HTTP session timeout that changed with a Exchange 2003  service pack when Direct Push came out back in 2005.  I remembered that setting and looked under the ISA Web Listener for ActiveSync on the Connections tab>Advanced>“connection timeout”.  The wizard had correctly set it to 1800 seconds (30 minutes). No dice.

I poked around the web listener settings some more and noticed the timeout settings for forms authentication were set (this same web listener was used for OWA).  ISA is supposed to be smart enough to not apply any of the forms auth settings to clients that don’t support it (falling back to basic auth as with ActiveSync).

ISA Web Listener Advanced Form Options

Tom and the forums at isaserver.org confirmed my suspicion.  The forms auth timeout was indeed affecting ActiveSync.  To find it, look for the web listener of your ActiveSync rule, go to properties>Forms tab>Advanced> and make sure “apply session timeout to non-browser clients” is unchecked. 

 

ISA 2006 from Edge Firewall to 3-Leg Perimeter

Published by Bret Fisher on Apr 16, 2009 in Microsoft, Networking and Security, Solution Writeups and Tech. 2 Comments Tags: , , , , , , .

ISA FirewallWhat if you want to take your simple 2 NIC “Internal/External” firewall and add a DMZ to it on the fly?  We recently tried this on a production firewall no less and hoped it would work.  It did after a few bumps. 

The big problem with changing your Network Template is that ISA wants’ to slick your config and start over, so you’ll end up with two options: Try to make a 3 NIC config work in  your original design by adding in networks and network rules, or applying a new network template and then bringing your config back in via import.  After failing the former (likely my lack of skills), we chose the later.

Mileage may very, but here’s some notes on what we did:

  • Obviously you need the 3rd NIC installed first.
  • Add the Subnets to the new NIC’s IP config for your DMZ aka “Perimeter” network in Windows.
  • Export your firewall config, including all settings, make a copy of the XML file, and open for editing.
  • We’re going to remove the network section of the XML file to prevent issues later.  Once you’ve chosen a new network template, you’ll want to import the config back in, minus the network related stuff (which is what the network template will change for  you).
  • Search the XML file for the open and closing NetConfig tags:
  • <fpc4:NetConfig StorageName="NetConfig" StorageType="1">
  • </fpc4:NetConfig>
  • Remove everything between these two tags and save the file.
  • Run through the network template wizard for 3-leg perimeter.  If clicking finish generates errors, work through them and come back to try again.  Our single error was because we had web listeners using HTTP compression, so we removed all objects from “General > Define HTTP Compression > Return Compressed Data” and added them back in later after re-import.
  • Once template wizard works, notice the lack of rules in your firewall policy and missing objects.  About now your thinking “OMG you screwed me!”, so import your augmented config and they should all be back. 
  • You’ll likely have a few dupe firewall rules if you chose a template firewall policy other then “block all”.  Sort your rules by the various columns to look for dupes.  We had dupes for “Allow Internal Routing” and “VPN Clients to Internal Network”.
  • Lastly go through your rule list and ensure the From/To columns are filled in.  You’ll want to restart the firewall service at this point to be sure it can start properly, and if it fails it’s likely a rule that won’t work in the new network config.  Check event logs for hints.  We had several rules we deleted and recreated based on new network names.

    • Ping Windows 2008 with Firewall On

    Published by Bret Fisher on Mar 12, 2009 in Microsoft, Networking and Security and Tech. 3 Comments Tags: , , , , , .

    You should be trying hard to keep the firewall on when deploying Windows Server 2008.  If you need to ping the server and haven’t enabled File and Printer Sharing, then open Windows Firewall with Advanced Security and under Inbound rules, enable “File and Printer Sharing (Echo Request – ICMPv4-In)”.  Might as well enable ICMPv6 while your at it.

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