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Posts Tagged ‘security’

Forefront TMG 2010 Computer Certificate Request or Renewal Fails

April 21, 2014 2 comments

When attempting to request or renew a computer certificate on the Forefront TMG 2010 firewall, you may receive the following error message:

Status: Failed
The RPC server is unavailable.

 

forefront_tmg_2010_certificate_01

This occurs because the Forefront TMG 2010 firewall does not, by default, allow the protocols and ports required to request or renew a certificate from a Certificate Authority (CA). Common workarounds suggest stopping the firewall completely or creating a rule allowing all protocols and ports from the TMG firewall to the CA. However, both of these workarounds are problematic. Stopping the firewall is a manual process that will cause a service disruption. It also leaves the firewall in an unprotected state. For edge deployment scenarios, the underlying operating system will be exposed directly to untrusted networks, which is a serious security risk. Creating an open access rule is not desirable because it violates the basic security principle of least privilege by allowing more access than is required.

To properly address this issue and allow for the secure request and renewal of certificates without disruption and with the least exposure, it will be necessary to create an access rule on the Forefront TMG 2010 firewall to allow all dynamic ports (TCP 49152-65535) from the local host network to the IP address of the CA for all users.

forefront_tmg_2010_certificate_02

Note: Allowing all dynamic ports (TCP 49152-65535) might also be considered too much access from the Forefront TMG 2010 firewall to the CA. It is possible to restrict the dynamic ports used by TMG and further tighten the access rule, if required. For information about restricting dynamic ports, click here.

In addition to the access rule allowing all dynamic ports, it will also be necessary to make a change to a system policy rule. To do this, right-click the Firewall Policy node in the navigation tree and choose All Tasks, System Policy, and then Edit System Policy. In the Authentication Services group highlight Active Directory and clear the checkbox next to Enforce strict RPC compliance.

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Once these changes have been made you can now request or renew a computer certificate on the Forefront TMG 2010 firewall successfully.

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Windows Azure Multifactor Authentication and Forefront TMG 2010

November 12, 2013 1 comment

When Microsoft first announced Windows Azure Multi-Factor Authentication, a cloud-based strong authentication solution, my first thought was “I wonder if it works with Forefront TMG 2010?” Being cloud-based, my first thought was perhaps not. However, once I started digging in to it I quickly learned that it includes a software component that can be installed on-premises and will even integrate with on-premises security solutions via a number of interfaces, including RADIUS. Forefront TMG 2010 has supported RADIUS authentication for many years, so I put together a test lab and in no time at all I had Windows Azure multi-factor authentication working with Forefront TMG 2010 remote access VPN. Forefront TMG 2010 integrated with Windows Azure multi-factor authentication provides the highest level of protection for remote access users. Leveraging Windows Azure cloud-based strong authentication is extremely cost effective, with very low per user or per authentication costs and no on-premises hardware to purchase. The Windows Azure public cloud, which is ISO/IEC27001:2005 certified, provides the most secure and reliable strong authentication service available today. To learn how to configure Forefront TMG 2010 to work with Windows Azure multi-factor authentication, click here.

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Improving SSL Security for Forefront TMG 2010 Published Web Sites

October 8, 2013 Comments off

Recently I wrote an article for ISAserver.org entitled Improving SSL Security for Forefront TMG 2010 Published Web Sites. In the article I demonstrate how to evaluate the current security configuration of your Forefront TMG firewall for published SSL web sites and how to make changes to the default settings in order to improve the overall security posture of TMG in reverse proxy scenarios. Implementing these changes will provide dramatically improved protection for Forefront TMG published SSL web sites. The steps outlined in the article include details for changes to be made to specific registry entries on the Forefront TMG 2010 firewall. I’ve had a number of requests to make the registry file available for download in order to simplify the process and ensure that these changes are made correctly. You can download the registry file used in the ISAserver.org post here. Enjoy!

Extending the Life of Forefront TMG 2010 with Zscaler Cloud Based Security

September 16, 2013 6 comments

Forefront TMG End of Life

With the end of life announcement for Microsoft Forefront TMG 2010, one of the most common questions I am asked is “What should I replace my Forefront TMG firewall with?” Many are surprised when I reply “Why do you want to replace it?” Simply because Forefront TMG will not be developed in the future does not mean there’s an immediate need to replace it. Considering the fact that Forefront TMG mainstream support extends until April 2015, and extended support lasts until April 2020, often the decision to replace TMG is nothing more than a knee-jerk reaction to marketing pressure by vendors of competing solutions.

Do You Need to Replace Forefront TMG 2010 Now?

If you have deployed Forefront TMG 2010 as a firewall, basic forward or reverse web proxy, or remote access or site-to-site VPN, there is no need to replace Forefront TMG 2010 right now. All of the features used in these deployment scenarios will continue to function in to perpetuity. You have until April 2020 to find a replacement for Forefront TMG, which should give you plenty of time to consider alternative solutions. However, if you have deployed Forefront TMG as a secure web gateway, the situation is a little different. Although support for the product extends until April 2020, the Web Protection Service (WPS) subscription will only function until the end of 2015. This means that URL filtering reputation database updates, antimalware signatures, and Network Inspection System (NIS) signatures will no longer be updated past this time. Not to worry, there are some excellent cloud-based security solutions that can be integrated with Forefront TMG 2010 to effectively extend the life of TMG for the foreseeable future.

Extending the Life of Forefront TMG 2010 with Zscaler

Recently I had the opportunity to evaluate the Zscaler Cloud-based security solution. Zscaler provides security-as-a-service and integrates seamlessly with Forefront TMG to provide essential web security protection with URL filtering, dynamic web content control, virus and malicious software scanning, HTTPS inspection capabilities, and more. The Zscaler security solution provides significantly more protection than the native Forefront TMG technologies offer. There are also tremendous economies of scale to be gained by using this cloud-based security solution, as Zscaler has more than 4000 enterprise customers in 180 countries, servicing more than 10 million users globally. The threat intelligence gained from having such a broad view of Internet activity worldwide enables Zscaler to quickly identify emerging threats on a global basis and extend protection to all of its customers quickly and effectively.

Zscaler Integration with Forefront TMG 2010

Integrating an on-premises Forefront TMG firewall with the Zscaler cloud is accomplished without having to install a plug-in on the TMG firewall. On-premises web traffic is delivered to the Zscaler cloud service by Forefront TMG through the use of web proxy chaining rules. After you’ve signed up for the service, simply configure a web proxy chaining rule to forward web proxy requests from Forefront TMG to the Zscaler cloud proxy gateways.

Forefront TMG 2010 Zscaler Web Proxy Chaining Configuration

Forefront TMG 2010 Zscaler Web Proxy Chaining Configuration

Zscaler Protection for Mobile Users

The Zscaler solution has some additional advantages over Forefront TMG’s native web protection mechanisms. With a cloud-based solution, Zscaler’s protection can also be extended transparently to mobile users, keeping them safe regardless of where they are. Zscaler has more than 100 datacenters worldwide, ensuring quick response times and low latency wherever the mobile user happens to be. Integrating individual clients can be done using proxy PAC files to route traffic to Zscaler’s datacenters. Additionally there is an option to install an agent on the client to forward traffic, which has the benefit of preventing the end user from disabling proxy settings to bypass content filtering restrictions.

Forefront TMG 2010 and Zscaler – Better Together

You may be asking yourself “Why not just use Zscaler exclusively? Why do I need TMG at all?” Valid question! Integrating Zscaler with Forefront TMG provides the best of both worlds in terms of security and performance. With Forefront TMG 2010 on premises, you have a Common Criteria-certified enterprise-class firewall to provide the highest level of security for your network. You can leverage strong user and group-based authentication, and you gain the added benefit of local caching for web content. In addition, you can make use of Forefront TMG 2010’s other features like multi-networking to create perimeter or DMZ networks for isolating public-facing services, reverse proxy for on-premises web-based and non-web based applications and services, remote access VPN for managed and non-managed mobile users, and site-to-site VPN to connect remote offices, business partners, or cloud service providers.

Forefront TMG End of Sale? Not Quite!

Although Microsoft is committed to supporting Forefront TMG 2010 for many years to come, they are no longer selling Forefront TMG 2010 licenses or the Web Protection Service (WPS) subscription licenses. If you’ve already deployed Forefront TMG 2010, or have already purchased Forefront TMG processor licenses and the WPS subscription, you have nothing to worry about. If you’re looking to deploy Forefront TMG 2010 today, you can’t purchase licenses for the software from Microsoft. However, you can still obtain Forefront TMG 2010 through a Microsoft OEM partner like Celestix Networks. (Full disclosure: Celestix Networks is my current employer.)

Keep Calm and Carry On

In my estimation, you can safely deploy or keep Forefront TMG 2010 in your environment and still gain a healthy return on your investment for many years to come. If you’re using Forefront TMG for publishing services such as Outlook Web App (OWA) or SharePoint, or you’re leveraging client-based remote access or site-to-site VPN, you have nothing to worry about. If you’re using Forefront TMG as a secure web gateway, you can enhance and extend the solution by using Zscaler’s cloud-based security solution for less than you would have paid for the Microsoft WPS subscription. No need to go out and replace your Forefront TMG 2010 solution for quite a few more years! If you are considering a new deployment, you can still purchase Forefront TMG 2010 from Microsoft OEM partners like Iron Networks. So Keep Calm and Deploy Forefront TMG 2010 today!

Keep Calm and Deploy Forefront TMG 2010!

Win a Copy of Windows Server 2012 Security from End to Edge and Beyond

As many of you know, I recently joined the team at Iron Networks to work more closely with DirectAccess and to be involved with some of their exciting new solutions for enabling the Microsoft private cloud. I was noticing that they don’t have much of a following on Twitter yet, so in an effort to change that I’m announcing a Twitter contest! This Friday, May 31, I will select one individual who is following both me and Iron Networks on Twitter and send you a free copy of Tom and Deb Shinder and Yuri Diogenes’ latest book entitled “Windows Server 2012 Security from End to Edge and Beyond”. I had the privilege of serving as the book’s technical reviewer and I can tell you it is an excellent reference that you’ll want to have in your library. So go out and follow me and Iron Networks for a chance to win!

Iron Networks

Windows Server 2012 Security from End to Edge and Beyond

Windows Server 2012 Security Book

January 11, 2013 Comments off

Great news! Windows Server 2012 Security from End to Edge and Beyond is now available for pre-order! Yuri Diogenes along with Tom and Deb Shinder are the authors of this forthcoming title from Syngress Publishing which covers architecting, designing, planning, and deploying Windows Server 2012 security solutions. I have the privilege of serving as the technical reviewer of the book and I can tell you from experience it will be a vital reference that anyone working with Windows Server 2012 will want to have in their library. Pre-order your copy today!

Windows Server 2012 Security from End to Edge and Beyond

Forefront TMG and UAG 2010 Presentation at TechEd North America 2012

June 19, 2012 Comments off

For those of you who were not able to attend Microsoft TechEd North America 2012 this year, the session I presented entitled “Demystifying Microsoft Forefront Edge Security Solutions: TMG and UAG” is now available online. Enjoy!

Forefront TMG and UAG Presentation at TechEd North America 2012