Testing Your Internet Facing Infrastructure

If you are an organisation with any Internet facing resources, it’s important for you to ensure that all the supporting infrastructure is alive, well, and functioning as it should be.  For large institutions, you probably already have all sorts of monitoring in place that can tell you of any problems in near-real time. You do, don’t you?
If you don’t (or you want to augment your existing services) there are number of sites on the Internet that will do that for you and provide you with the results. One site, Pingdom.com provides both a free and a pay service.
The pay service is aimed at monitoring the uptime and performance of you servers, including not only your corporate web server, but others too such as your Lync Edge server.  The Pingdom  service provides real-time monitoring service that can alert you is something interesting happens. You can get alerts ins SMS, Twitter and E-mail. The service also keeps records of the tests performed and the results which enable you to keep track of the performance of your key web sites. You can even get alerts on your mobile phone (Android and IOS it looks like – no Windows phone). 
And there’s even a REST-based API for you to use! The API produces JSON encoded output. Invoking the API and interpreting the JDON responses were features added to PowerShell V3 – thus with the pay-service APIs, you could write PowerShell scripts to manage your Pingdom service!
If you are a Lync Admin, and are providing either remote access (i.e. to your users who are coming in via the Internet) or are providing federation to customers and clients, you have a significant challenge to setup your external infrastructure and ensuring it continues to function. The pay service can provide you with a useful set of eyes/ears on the internet, ensuring that all the infrastructure aspects of your Lync Internet features are working as they should – and will inform you when that stops.
Pingdom also offers three sets of free tests for you to use:

• Ping/Traceroute – provides basic ping and traceroute to your site from Pingdom’s site. This provides a useful point of view in terms of your infrastructure’s availability/reachability across the Internet. The ping comes from one of the many probe servers used by Pingdom - there are over 60!
• DNS Health – this page checks to see if external Internet DNS is setup correctly. DNS setup is critical to ensure your site is reachable but is also easy to misconfigure. This page tests your infrastructure, and provides details as to what it finds: good or bad. There’s also a troubleshooting guide to help you to understand the errors that the checker might find and how to resolve them. See here to see what precisely the DNS test is doing for you.
• Full Page Test – this page tests the performance of a web page on your site and returns a wealth information.  The waterfall view shows all the files that downloaded and how long each download takes.  The Performance Grade view shows you how your page performs against a benchmark set of metrics. The Page Analysis view analyses the download, providing details of the server response code, how the page loaded, what sorts of documents are being downloaded, etc.

Here’s an example of using the Full Page Test against my Office 365 site, Reskit.Net:

This site is a fairly simple SharePoint site – and you can see each of the individual files downloaded to make up the page and what’s happening during the downloading of each file. You can use this waterfall graph to possibly optimise the page for faster downloads (and less bandwidth used).
And speaking of Free, Pingdom also provides a free check of a single site. This is the same check you could perform using their paid service, but free. The pay service allows you to check more than one site/page, and other services (see https://my.pingdom.com/account/subscription for details of the pay version).
All in all these free tools are pretty good – and I discovered a small DNS configuration issue I need to resolve! Nice catch Pingdom. And the pay tools look like being useful as well.

Technorati Tags: Lync,Monitoring,PowerShell

Creating an NLB Cluster using Windows Server 2008

As noted in an earlier blog post, I’m writing an article on Server Clustering for Server Management Magazine. In the article I discuss setting up of an NLB cluster. This blog post shows the steps in more detail, including screen shots of each step.

Creating an NLB Cluster

There are three key steps to creating an NLB cluster in Windows Server 2008:

1. Install the NLB Feature into Server 2008 on each host that you will add to an NLB cluster.
2. Use the New Cluster wizard to create the cluster and add the first host.
3. Use the Add Host wizard to add one ore more nodes to your cluster

You also have to setup the application that you want to cluster. For the article I created a very simple ASP.NET application that I documented in an earlier blog post.

Installing NLB in Server 2008

This is extremely easy. First you run Server Manager, and select Features from the tree and click on Add Features:

From the Add Features wizard just select Network Load Balancing and click Next:

Finally from the Confirm Installation Selections click Install:

After a few seconds, NLB will be installed on the first host. You need to repeat this installation on each host you plan to add to your NLB Cluster. Installing the NLB feature does NOT require a reboot, but removing it does.

Creating your NLB Cluster

Once NLB is installed, you create your cluster by first bringing up the NLB Cluster Manager:

The right click the Network Load Balancing cluster node in the left pane, and select New Cluster:

This brings up the first page of the New Cluster Wizard – here you select the first member of your cluster by adding the IP address or DNS name into the Host box:

This shows you the interfaces on this host that you can use for configuring a new cluster. Chose the interface and click Next:

This brings up the Host Parameters page, where you enter the IP address to be used for the cluster for the cluster, then you click next:

 

This brings up the Cluster IP address page. Here you add the address used by clients to connect to nodes in the cluster:

 

After adding the IP address, and clicking next, the New Cluster wizard displays the Cluster Parameters where you specify the cluster IP configuration and the cluster operation mode (and click  next):

Finally, the wizard displays the port rules. In this case, we specify the cluster shoudl handle TCP Port 80 (and click on Finish):

The Wizard then does the necessary configuration, resulting in a single node NLB cluster, shown in the NLB manager like this:

At this point, you can navigate to the cluster to see the application running:

 

Adding Additional Nodes

A single node cluster is not much value, so you next need to add an additional node (or nodes). To add a node, you right click your newly created cluster and select Add Host to Cluster:

 

This brings up the Add Host to Cluster: Connect page where you specify the host to add, and the interface used in the cluster:

Next you specify the new host’s parameters:

Then you get to update, in needed the cluster’s port rules:

Clicking next completes the wizard, resulting in a 2nd host in the cluster. As seen by NLB Manager:

Re navigating in your browser to the cluster may (or may not) result in a different page. Whilst running the wizard to create the screen shots shown here, this did change:

 

So – it’s simple and easy to create an NLB cluster in Server 2008!

Technorati Tags: NLB,network load balancing,Windows Server 2008

DNS Expert and Book Author Cricket Liu To Present Designing a resilient DNS/DHCP Network

 Now this is cool - one of  my all time net-god heroes, Cricket Liu, is in town (London) to present a seminar entitled Designing a resilient DNS/DHCP Network. A chance to hear Cricket speak - you bet I'll be there.

Technorati tags: Cricket Liu, DNS, DNS God, DNS NET GOD

NetMon Blog

In a recent article, I wrote about the new beta of Network Monitor 3. It's an awesome product that I'm slowly getting aroud to using and understanging. The Network Monitor team also have a blog which has some good articles on the new version of NetMon. If you are a network geek, get on the beta, download it, and start playing!

Network Monitor 3 in public beta

I've been a heavy user of Microsoft's network monitor. Delivered as part of Windows Server and SMS (the latter a fuller version), it's a nice tool for capturing and analysing network traffic. It's not been updated for years - allowing WireShark (Ethereal as it used to be known) to take a lead in terms of functionality.

But MS has been hard at work with Netmon 3, which is now in public beta. Network Monitor 3 is a total re-write of capture engine, parser engine, and user interface. It runs on Windows XP and Vista, Windows Server 2003 and Longhorn; and is available in 32-bit and 64-bit versions.

One of the coolest new features is display while capturing - you can see the packets as they are captured. Neat!

To get this, go to http://connect.Microsoft.com, logon using your MS Passport ID. Then click on Available Connections and select Network Monitor 3.0. The download is just 3mb!

Thanks to Nick Portlock for pointing out this cool beta.

Technorati Tags: network monitor - microsoft - tool

Wireshark - a new name, but the software's the same

Last Thursday, I resigned from QA and with that resignation, I now feel I am now able to blog again. Horray! I'll be posting more deails about my next job during the coming week.

I was searching this morning and discovered that that well known Ethteral protocol analyser has changed its name to Wireshark. While the is new, the software is the same (and it continues to improve!).

Wireshark's powerful features make it a great tool for all serious network admins. I used earlier version in the development of my TCP/IP books. It's a great product all the more so since it's free to use. For more information about Wireshark, see the FAQ.

Wireshark was written by networking experts around the world, and is an example of the power of open source. It runs on Windows, Linux, UNIX, and other platforms. The latest version 0.99.2 was released in mid-July and contains a number of fixes plus new features. The updates also include a number of fixes to potential security issues. New features include improvements to the dissectors (protocol analyssers). This version also includes support for new protocls (e.g Bluetooth, Cisco WIDS, TiVo, etc) plus updatesto a large number of protocols.

You can download the latest windows version as well as full source code from the Wireshark site.