With the beta release of Windows Server 8 today, Internet Information server (IIS) 8 is available to the public for testing and even production workload testing. Many system administrators have been anxious to kick the tires and to find out which features are coming.
I’ll include a high level overview of what we will see in the upcoming version of IIS. The focus with this release of IIS 8 is on the large scale hoster. There are substantial performance improvements to handle thousands of sites on a single server farm—with ease. Everything that I mention below is available for download and usage today.
Forgive me if there are typos. I’m writing this while at the MVP Summit in Seattle while trying to listen to another session at the same time. Thanks to the IIS team who gave detailed demos on this yesterday and gave me permission to talk about this.
Real CPU Throttling
Previous versions of IIS have CPU throttling but it doesn’t do what most of us want. When a site reaches the CPU threshold the site is turned off for a period of time before it is allowed to run again. This protects the other sites on the server but it isn’t a welcome action for the site in question since the site breaks rather than just slowing down.
Finally in version IIS 8 there are kernel level changes to support real CPU Throttling. Now there are two new actions for sites that reach the CPU threshold. They are Throttle and Throttle under load. If you used WSRM to achieve this in the past, you no longer need to do so, and the functionality is improved over what is available with WSRM.
The throttle feature will keep the CPU for a particular worker process at the level specified. Throttling isn’t applied to just the primary worker process, but it also includes all child processes, if they happen to exist.
The Throttle under load feature will allow a site to use all possible CPU if it’s available while throttling the worker process if the server is under load.
The throttling is based on the user and not specifically on the application pool. This means that if you use dedicated users on more than one app pool then it throttles for all of app pools sharing the same user identity. Note that the application pool identity user is unique so if you use the app pool identity user—which is common—then each app pool will be throttled individually.
This is a welcome new feature and is nicely implemented.
SSL Scalability
Unless you deal with large scale site hosting with many SSL certificates you may not have realized that there is room for improvement in this area.
Previous versions of IIS have limited secure site density. Each SSL site requires its own IP address and after adding a few SSL sites, startup performance becomes slow and the memory demand is high. Every certificate is loaded into memory on the first visit to an SSL site which creates a large memory footprint and a long delay on the first load.
In IIS 8 the SSL certificate count is easily scalable to thousands of secure sites per machine with almost instantaneous first-loads. Only the certificate that is needed is loaded and it will unload after a configurable idle period. Additionally, enumerating or loading huge numbers of certificates is substantially improved.
SNI / SSL Host Header Support
Using host headers and a shared IP address with SSL certificate has always been problematic. IIS 8 now offers Server Name Indication (SNI) support which allows many SSL sites to share the same IP. SNI is a fairly new feature (within the last few years) which allows host headers to work with SSL. It does this by carrying the target host name in the TLS handshake rather than the encrypted part of the packet.
IIS 8 makes SNI support a first class citizen in the site bindings.
Note that SNI doesn't work on all browsers. For example, Internet Explorer in Windows XP does not support SNI. Read more about that from Eric Law's blog post. Over 85% of browsers is use today support SNI, but since it's not 100%, it will not work universally. However, like the adoption issue with host headers in the '90s, it will a fully supported before we know it. More details with a list of browsers can be found here: http://en.wikipedia.org/wiki/Server_Name_Indication
This sets the stage for sharing IP addresses which is extra important as ipv4 IPs become more valuable and consolidation of IPs becomes the trend.
SSL Manageability - Central Certificate Store (CCS)
In IIS 7 managing SSL is labor intensive, particularly for server farms. All certificate must be imported on every machine in the farm. When setting up new servers you must account for time needed to import certificates when scaling out, and even on small server farms. In previous versions keeping certificates in sync between servers is difficult to manage and often requires manual steps.
In IIS8 there is a new Central Certificate Store (CCS). Central Certificate Store allows storing certificates on a central file share instead of each machine. You can point the servers to a single network share, or use replication like DFS-R to sync the folders between machines.
Renewal and syncing is as simple as xcopying pfx files to the location that you specify when enabling CCS on the web server. Enabling CCS is straight forward too. It works very similar to enabling Shared Configuration.
CCS compliments the SNI functionality to support sites with multiple certs and a single IP.
The mapping of bindings to certificates uses a bit of magic … by convention rather than configuration. This is important for extremely large lists of certificates. Now you don't need to select them from a huge list. The value of the host header needs to match the name of the cert. Your CCS folder will have many .pfx files with names that match the domain name. Basically the name of the .pfx files in the certificate store is the primary key.
If you use a wildcard cert then it needs to be named _.domain.com.pfx.
As you would assume, there is support for Multiple Domain Certificates (Unified Communications Certificate [UCC]). If you use multiple domain certificates using the subjectAltName feature of the certificate then you just create multiple copies of the pfx, one for each subjectAltName.
Note that you can use the old method which binds to by certificate identifier and it works the same as it did in the past.
Furthermore there is a neat feature for the central repository that allows grouping by expiration date, which groups by "Today / This Week / Next Week / Next Month / Later" which is handy for seeing which certificates are ready to expire.
With these changes to the certificates, it makes for a powerful solution for large scale webfarm hosting with multiple tenants.
Dynamic IP Restrictions
Information about this is already available on the web, but it's moving along and getting closer for the final release.
FTP Logon Restriction
Yay. A new FTP IP Restrictions module is coming! This is similar in concept to Dynamic IP Restrictions for HTTP. One of the key differences is that it does gray listing rather than black listing. When someone is blocked, they are only blocked for the sample period (e.g. 30 seconds). This is nice because it's enough to thwart or slow brute force and common name password attacks, but legit invalid attempts can continue to attempt to log in without waiting for long periods of time.
What's extra nice about having this feature is that you can set it slightly more sensitive than your domain username lockout policy so that brute force attacks don't cause your username to be locked out from too many invalid attempts. The FTP IP Restrictions can throttle the hack attempts without locking out your domain users.
Application Initialization Module
Previously known as the application warm-up module which was pulled for a time, now it's ready in full force as Application Initialization Module.
This allows spinning up sites and pages before traffic arrives and handling of requests in a friendly way while the application first loads. It's not uncommon for a site to take a minute or longer on the first load (yes SharePoint admins, we feel your pain). This allows you to protect the end user from being the person that triggers this.
It's possible to set a warm-up page at the server level as a single setting, or you can use powerful URL Rewrite rules for more flexibility.
You can also ensure that your load balancer’s health test page doesn’t serve up a valid response until the site is fully initialized according to your preferences. Then the load balancer will bring a node into rotation only after the entire warm-up has completed.
Configuration Scale
The IIS configuration files (e.g. applicationHost.config) can handle very large files with ease now. There are substantial performance improvements in the upcoming version. Only administrators with large numbers of sites on the same server or server farm (think thousands) would have noticed before, but for large scale performance the new changes are paving the way for huge scale.
Web Sockets
It’s important to include Web Sockets in this list too. Apart from some brief information I really haven’t looked into Web Sockets in detail yet so I’ll just include a great link from Paul Batum on it. Web Sockets does require Windows 8 or later on the server side.
All in all these are welcome changes. While previous versions of IIS already did a great job of handling massive amounts of traffic, IIS 8 now can handle thousands (or tens of thousands) of sites and their extensive configurations on a single server farm. With HTTP and FTP logon restrictions, CPU throttling, the Application Initialization Module, and large scale SSL and configuration improvements, IIS 8 brings a number of welcome improvements.
You can find this week’s video here.
This lesson covers ways to troubleshoot IIS FTP. When it works, it works well, but if you run into issues getting an FTP account working it can sometimes be difficult to resolve. This video will help you understand some helpful tricks and it will walk you through ways to isolate and resolve the issue.
Over the last five weeks we’ve been looking at IIS FTP. See the list below to jump to a specific FTP topic. This week we explore some troubleshooting techniques and review the following FTP connectivity stack.
- DNS Resolution/Network Connectivity
- Firewall Access (Passive/Active / Secure?)
- IIS Bindings
- Authentication
- Authorization
- Isolation Mode / File paths
- NTFS Permissions
There were two external resources which I referenced. They are:
This is now week 48 of a 52 week series for the web pro and it is the final of a 5-week mini-series on IIS FTP. The five weeks include:
You can find this week’s video here.
You can find this week’s video here.
Have you ever wondered what FTP Active mode or Passive mode means? Do you have a good understanding of the FTP data channel or control channel? It can be difficult to fully understand FTP, which firewall ports to enable, and how to navigate the two communication channels. This lesson will hopefully clear up these questions and more.
This week’s video lesson takes a deep dive into FTP Active vs. Passive modes. As part of this you’ll get a chance to see the various modes in action, see what the traffic looks like in Wireshark, see exact firewall rules, learn about stateful FTP, find out about Explicit FTPS and Implicit FTPS, and learn about the FTP data channel and control channels.
This week's video lesson is the 4th of a 5-week mini-series on IIS FTP. The five weeks include:
- Week 1: IIS FTP Basics
- Week 2: IIS FTP and IIS Manager Users
- Week 3: IIS FTP and User Isolation
- Week 4: IIS FTP Firewall settings, Active vs. Passive
- Week 5: IIS FTP Troubleshooting plus FTP Host Headers
This is now week 47 of a 52 week series for the web pro, and the 4th of a 5 week mini-series on IIS FTP. You can view past and future weeks here: http://dotnetslackers.com/projects/LearnIIS7/
You can find this week’s video here.
Today I wanted to find a way to flush the IIS FTP logs on-demand. The logs for IIS FTP flush to disk every 6 minutes, and the HTTP logs every 1 minute (or 64kb). This can make troubleshooting difficult when you don’t receive immediate access to the latest log data.
After looking everywhere I could think of, from search engine searches to perusing through the IIS schema files, I figured I had better go to the source and ask Robert McMurray.
Sure enough, Robert had the answer and even wrote a blog post in response to my question with code examples for four scripting/programming languages (C#, VB.NET, JavaScript, VbScript).
There is not a netsh or appcmd solution though, so the scripting or programming options are the way to do it. Actually, you can also flush the logs by restarting the Microsoft FTP Service (ftpsvc) but, as you would assume, it will impact currently active FTP sessions.
This blog post serves three purposes.
- It’s a reference pointing to Robert’s examples
- I’ll include how to do the same for the HTTP logs
- I’ll provide a PowerShell example which I based on Robert’s examples
1. The reference is mentioned above already, but to give me something useful to write in this paragraph, I’ll include it again. Programmatically Flushing FTP Logs.
2. For HTTP there is a method to flush the logs using netsh.
netsh http flush logbuffer
This will immediately flush the HTTP logs for all sites.
3. The FTP logs can be done from PowerShell too. Here’s a script which is the PowerShell equivalent of Robert’s examples. Just update $siteName, or pass it as a parameter to the script.
Param($siteName = "Default Web Site")
#Get MWA ServerManager
[System.Reflection.Assembly]::LoadFrom( "C:\windows\system32\inetsrv\Microsoft.Web.Administration.dll" ) | Out-Null
$serverManager = new-object Microsoft.Web.Administration.ServerManager
$config = $serverManager.GetApplicationHostConfiguration()
#Get Sites Collection
$sitesSection = $config.GetSection("system.applicationHost/sites")
$sitesCollection = $sitesSection.GetCollection()
#Find Site
foreach ($item in $sitesCollection){
if ($item.Attributes.Item("Name").Value -eq $siteName){
$site = $item
}
}
#Validation
if ($site -eq $null) {
Write-Host "Site '$siteName' not found"
return
}
#Flush the Logs
$ftpServer = $site.ChildElements.Item("ftpServer")
if (!($ftpServer.ChildElements.Count)){
Write-Host "Site '$siteName' does not have FTP bindings set"
return
}
$ftpServer.Methods.Item("FlushLog").CreateInstance().Execute()
I hope one of these programming/scripting options come in handy for times when you want immediate access to the latest FTP log data.
You can find this week’s video here.
I’ve been looking forward to releasing this week’s video. IIS FTP User isolation is an interesting topic because it offers a lot of power and flexibility but it’s not very intuitive because of how it’s managed.
This week we walk through the five isolation modes to gain a full understanding of the IIS FTP method of configuration for user isolation.
IIS FTP is a powerful application, but some of the flexibility is hidden through a unique convention based method of management. It’s easy to miss the fact that IIS FTP allows the ability to have multiple users who can be directed to different folders and be fully isolated from each other. For example, you can have a designer1 who has access to the whole site while designer2 has access to just project1 only, while—if you set it up correctly—you can feel confident that designer2 can’t gain more access than they are allowed.
IIS FTP requires understanding a few core principles to manage it effectively and to ensure that you don’t overlook key security settings that would allow users to gain more access than they should. IIS FTP 7.5 offers five different isolation modes, each of which targets a different situation.
This is now week 46 of a 52 week series for the web pro, and the 3rd of a 5 week mini-series on IIS FTP. You can view past and future weeks here: http://dotnetslackers.com/projects/LearnIIS7/
Also, if you’re reading this early enough, I’m taking questions for the last couple weeks of the series. Read more about it here.
You can find this week’s video here.
A question came up on a blog post of mine on how to redirect a domain name that doesn’t have www in it while retaining the original domain name. Basically, to have a generic redirect to add on a www if it’s not already there.
For example, how could you have something.com always redirect to www.something.com where something could be any of a number of domain names that you manage.
This is fully possible with URL Rewrite. Here’s what the config looks like. If you want a full walkthrough using the setup wizard then refer to my previous post for the details.
<rule name="non-www to www" enabled="true" stopProcessing="true">
<match url=".*" />
<conditions>
<add input="{HTTP_HOST}" pattern="^[^\.]+\.[^\.]+$" />
</conditions>
<action type="Redirect" url="http://www.{HTTP_HOST}/{R:0}" />
</rule>
This rule watches for all 2 level domains and redirects to the same domain name and tacks on the www to the beginning. So something.domain.com won’t be redirected, but domain.com will.
Alternately, if visitors will come in through either http or https, you can ensure that this retains the protocol with 2 rules, one for each:
<rule name="non-www to www http" enabled="true" stopProcessing="true">
<match url=".*" />
<conditions>
<add input="{HTTP_HOST}" pattern="^[^\.]+\.[^\.]+$" />
<add input="{HTTPS}" pattern="off" />
</conditions>
<action type="Redirect" url="http://www.{HTTP_HOST}/{R:0}" />
</rule>
<rule name="non-www to www https" enabled="true" stopProcessing="true">
<match url=".*" />
<conditions>
<add input="{HTTP_HOST}" pattern="^[^\.]+\.[^\.]+$" />
<add input="{HTTPS}" pattern="on" />
</conditions>
<action type="Redirect" url="https://www.{HTTP_HOST}/{R:0}" />
</rule>
You can find this week’s video here.
IIS FTP supports a new type of user called IIS Manager Users. This type of user can be used instead of Windows Local or Active Directory Users.
They are useful if you want to manage a number of FTP users but don’t want to use Windows Local Users or you want to keep IIS FTP separate from the operating system users. They are also compatible with Shared Configuration so you can create the users once and they will work on all servers in a web farm.
To properly manage IIS Manager users with IIS FTP, there are a few things to consider for security and configuration. This week I cover everything you need to know to properly support IIS Manager Users with IIS FTP. This is week 45 of a 52 week series, and the 2nd of a 4 week mini-series on IIS FTP.
Also, if you’re reading this early enough, I’m taking questions for the last couple weeks of the series. Read more about it here.
You can find this week’s video here.
If you’ve been following my 52-week series you most likely noticed that we’re nearing the end. This evening, for example, I’m recording week 47.
Predrag Tomasevic (see developer related articles he’s written) sent me an email and made a suggestion to make the last couple videos as a Q&A. I thought that would be a great idea. Let’s do it! I’ll accept questions for the next month or so and toward the end of January I’ll record the final two weeks as Q&A sessions.
Please use the comments section below to ask IIS or IIS related questions which you would like to see answered. Note that I approve all comments before they show up, otherwise the spammer overwhelm the comments, so your question may not show up immediately.
I’m targeting quicker Q&A questions rather than full walkthroughs, but feel free to ask any type of question you want and I’ll take on whichever questions that I’ll have time for, or which I hope to be able to give a reasonably worthwhile answer for. 
You can find this week’s video here.
The FTP (File Transfer Protocol) protocol has been in wide use for years and is still widely used today. It's used for transferring files between locations and practically useful for deployment websites from a dev machine or continuous integration server to staging or production websites.
Microsoft IIS FTP has evolved over the years and the latest versions are particularly powerful. It now supports all standard functionality that you would expect from an FTP server, plus FTP over TLS (secure FTP), host headers, IIS Manager user permissions, IP restrictions, greatly improved isolation options, and more.
This week's video lesson is the start of a 4-week mini-series on IIS FTP. The four weeks will include:
- Week 1: IIS FTP Basics
- Week 2: IIS FTP and IIS Manager Users
- Week 3: IIS FTP and User Isolation
- Week 4: IIS FTP Firewall settings and Troubleshooting
This first week I cover installing IIS FTP on IIS 7.0 and 7.5, setting up the site, authentication and authorization, security, and other general FTP discussion.
This is now week 44 of a 52 week series for the web pro. You can view past and future weeks here: http://dotnetslackers.com/projects/LearnIIS7/
You can find this week’s video here.
You can find this week’s video here.
IIS 7 has two application pool pipeline modes: Classic and Integrated. Using Integrated mode is the ideal since it allows forms authentication for all types of page requests—not just ASP.NET pages—has tighter integration with the entire pipeline, and will be leveraged by more native and 3rd party apps over time.
However, you may run into a “HTTP Error 500.22 - Internal Server Error” when trying to run your site in Integrated mode. This week we look at the differences and find out how to migrate a configuration file from IIS6 or IIS 7 Classic mode to IIS 7 Integrated mode.
The article referenced in the video can be found here. This gives a list of breaking changes with integration mode.
This is now week 43 of a 52 week series for the web pro. You can view past and future weeks here: http://dotnetslackers.com/projects/LearnIIS7/
You can find this week’s video here.
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