GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. A proxy server acts as a single point of contact serving clients on the request side or Web server workers on the response side.
IIS with URL Rewrite as a reverse proxy - part 2 – dealing with 500.52 status codes
On the request side, the proxy accepts a request from one of multiple clients, and forwards it to the Internet. To the Internet the request appears to be coming from the proxy, rather than from the client. On the response side, the proxy accepts a request from the Internet, and distributes it to one of multiple workers. To the Internet the request appears to be processed and a response appears to be generated by the proxy server itself, rather than from one of the backend workers.
The first type of proxy server, the one that handles an outbound request from a client, forwards it to the Internet, and returns the generated response to the client, is called a forward proxy. The second type of proxy server, the one that handles an incoming request from the Internet, forwards it to a backend worker, and returns the response to the Internet, is called a reverse proxy.
Forward proxies and reverse proxies have significantly different functions, but they both do the same fundamental action of serving as the proxy for a requester or responder. In both cases, the proxy server isolates the private network from the Internet, enabling you to take measures to improve security. In both cases, the proxy processes requests and responses, enabling it to perform operations on the traffic that can improve performance by using caching or compression, guard against attacks, and filter information.
When ARR serves as a forward proxy, it is part of an internal network or intranet of client computers. ARR as a forward proxy can be used to improve bandwidth usage and performance by caching; however, it is not suitable as a full-fledged, commercial-grade forward proxy.
When it receives a request from one of the clients naming the target Web server, the forward proxy server processes the request as follows and forwards it through the firewall to the Internet:. If Application Request Routing Version 3 has not been installed, it is available for download here. The download site displayed by this link includes installation instructions. For more information, see Installing IIS 8. In the server pane, double-click Application Request Routing Cache.
In the Actions pane, click Server Proxy Settings. On the Application Request Routing page, select Enable proxy. In the Actions pane, click Apply. This enables ARR as a proxy at the server level.Url Rewrite, one of the many modules that can be added on to the IIS web-server to make this a very versatile tool can be used to perform a variety of tasks, including allowing you to setup your IIS web-server as a reverse-proxy server to some other back-end HTTP service.
A reverse proxy is a network device that takes in traffic coming from the Internet for exampleand forwards this traffic to a backend server on your private network, allow that backend server to be accessible to people who are not necessarily connected to your network.
There are a lot of articles on how to use IIS and Url Rewrite as a reverse proxy, but I have found that many are incomplete with regards to real world scenarios from today's web applications. Details: suppose that we have a web-application hosted on one of our backend web-servers, IIS or another web server, and that this application server cannot be configured to use SSL and is not accessible to the end users because the end users do not have access to the network the server is on.
We want IIS to perform the following tasks:. Below is the diagram of the setup we wish to accomplish using IIS as a reverse proxy server:.
I would like to take you through the configuration steps required to setup such a system, where requests are routed via the IIS server to the backend application server and the re-written back again with the public host-name of the IIS server and sent back to the connecting clients. The first step is to install the add-on module for URL Rewrite. You can also download the extension from IIS.
This icon is present at the level or each site and web-application you have in the server, and will allow you to configure re-write rules that will apply from that level downwards. Chose the 'Add Rule' action from the right pane of the management console, and the select the 'Reverse Proxy Rule' from the 'Inbound and Outbound Rules' category.
Now we can proceed to fill in the routing information based on the diagram above in the Wizard window that is provided to us. While still in the same configuration window, we also need to provide information to take care of the responses that will be emitted by the backend server and will transit the IIS server on their way back to the requesting browser. These responses may have absolute hyperlinks inside and other information which contains the hostname of the backend server.
The basic setup for the reverse proxy is now complete, with IIS able to capture incoming traffic and forward it to the backend server, and inspect responses from the backend server and rewrite URL links inside the responses to match the host headers that IIS uses to publish the site.
Read on in part number 2 to see where the problems with this setup start. Skip to main content. Exit focus mode. We want IIS to perform the following tasks: Take in requests from the end users for content from this application using SSL Route these requests to the backend application server using HTTP Rewrite all responses from the backend server, so that any hyperlinks, form action tags and such are constructed with the URL that the IIS reverse proxy server has.
Below is the diagram of the setup we wish to accomplish using IIS as a reverse proxy server: I would like to take you through the configuration steps required to setup such a system, where requests are routed via the IIS server to the backend application server and the re-written back again with the public host-name of the IIS server and sent back to the connecting clients. Setup a Reverse Proxy rule using the Wizard.
Related Articles In this article.With ARR, administrators can optimize resource utilization for application servers to reduce management costs for Web server farms and shared hosting environments. ARR makes request routing decisions at the application level, and can be used in conjunction with hardware load balancers or Windows Network Load Balancing as an added layer of control over HTTP requests.
In addition, ARR enable hosting providers to route requests from clients to specific Web application servers in a server farm by creating an affinity between the client and server. ARR lets administrators and hosting providers create, manage, and apply load balancing rules to server farms in IIS Manager.
They can easily add or remove servers from a server farm to match demand throughput without impacting application availability. ARR also includes live traffic and URL test monitoring capabilities to determine the health of individual servers and configuration settings, while allowing administrators to view aggregated runtime statistics in IIS Manager. By combining the disk caching capabilities along with a hierarchy of IIS Web servers running ARR, CDNs and hosting providers are able to considerably reduce the network traffic that traverses up to the origin server.This material is provided for informational purposes only.
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Application Request Routing
The This can happen for multiple reasons - for example: failure to connect to the server, no response from the server, or the server took too long to respond time out. If you are able to reproduce the error by browsing the web farm from the controller, and detailed errors are enabled on the server, you may see an error similar to the following:.
The error code in the screenshot above is significant because it contains the return code from WinHTTP, which is what ARR uses to proxy the request and identifies the reason for the failure. You can decode the error code with a tool like err. The following is an excerpt from the IIS log entry for the This will help if you are tracing the target or destination of the HTTP request:. This generally indicates that the client ARR being the 'client' in this case had disconnected before the request completed.
In the IIS log entry from the ARR server, we can see that the time-taken is very close to 30 seconds, but the member server log shows that it took 45 seconds ms to send the response. This suggests that ARR is timing the request out, and if we check the proxy timeout in the server farm's proxy settings, we will see that it is set to 30 seconds by default.
So in this case we can clearly see that the ARR timeout was shorter than the execution of the request. Therefore, you would want to investigate whether this execution time was normal or whether you would need to look at why the request was taking longer than expected. If this execution time was expected and normal, increasing the ARR timeout should resolve the error. Looking at the first two examples, ResolveTimeout and ConnectTimeout, the troubleshooting methodology outlined above would not work.
This is because you would not see any traffic on the target server and therefore would not know the error code. To test this type of problem, create a simple. In the following example there is a directory called "time" which is configured with a simple aspx page as the default document of that directory.
When browsing to the directory, ARR will display this error:. The request can be traced to the server that actually processed it using the same steps used earlier in this troubleshooter, with one exception; while Failed Request Tracing on the destination server shows the request was processed on the server, the associated log entry does not appear in the IIS logs.
The built-in logs on the destination server do not provide any additional information about the problem, so the next step would be to gather a network trace from the ARR server. In the example above, the. Close without returning any data.This is the second article in a three-part series of articles dealing with setting up IIS as a reverse proxy.
Check out part one here. Testing this new setup for basic scenarios may work, but you can also be presented with a couple of issues. The first one is that you may have status codes when you try to access your backend server. Outbound rewrite rules cannot be applied when the content of the HTTP response is encoded "gzip".
Status code for this is This is because the responses that are coming from the back end server are using HTTP Compression, and URL rewrite cannot modify a response that is already compressed. This causes a processing error for the outbound rule resulting in the A client indicates to the server that it is willing to accept compressed content by indicating this in the http headers it sends to the server alongside the request.
This is indicated in the 'Accept-Encoding' Header. There are two ways to work around this: either you turn off compression on the backend server that is delivering the HTTP responses which may or may not be possible, depending on your configurationor we attempt to indicate to the backend server the client does not accept compressed responses by removing the header when the request comes into the IIS reverse proxy and by placing it back when the response leaves the IIS server.
I will only detail the second alternative, with regards to the removal and re-instatement of the HTTP header. Click this button to be able to add new server variables. Click the 'Add' button on the right hand side pane to add a new server variable.
Once this is complete, we will need to use these variables both in the inbound rules, to remove the Accept-Encoding header and in the Outbound Rules to place this header back again. Go to the Inbound Rules section in Url Rewrite.
This section should just contain one inbound rule, called 'Reverse Proxy Inbound Rule 1'. Select this rule and click the 'Edit' action link on the right hand side panel of the IIS Administration Console to be able to edit the details of this rule. In the 'Server Variables' section we will need to add the two server variables that we have declared earlier. This variable will be used by URL Rewrite when it builds the request to forward to the backend server. So if we do not wish this request to have an Accept-Encoding header, we must empty its value.
Press the 'Add' button again on the 'Server Variables' pane, and then fill in the 'Set Server Variable' window as follows:. Note that the interface will not allow you to set the variable's value to empty, hence you can set this to any arbitrary string I just use 'eee'. We will correct this manually in the configuration files afterwards. Once this is done, press the 'Apply' button to save the configuration changes to the IIS configuration store — in this case the web.
Open the web. Here you should find the InboundReverseProxyRule1 rule definition which should look like the snippet below:. The new line of configuration should look like the following:. Note: if you cannot save the file because of elevation privileges requirements, then you can save the web. This will require you to confirm the replace with an elevated prompt as well, but that should not be a problem. When we receive the responses from the backend server, we need to forward them back to the browser.Home IIS.
I have 2 SSL websites internally. Any help appreciated. According to your description, my understanding is that you would like set multiple web site to one ip and certificate. To better understand, I have two sites domain.
Download Microsoft Application Request Routing 3.0 (x64) from Official Microsoft Download Center
Internally accessing, they're both fine since they each have their own IP address and certificate. Accessing from outside, user requests either of the sites over https:external IP my router. ARR internal IP can only bind single certificate either domain. If I bind domain. You can only bind one certificate per website. If you want to use only one IP and website, you've got to have a certificate that has both names in it.
In your example, both domain. Oct 03, AM mr. I've been reading this thread and others like it. There is something about the replies to the question I don't understand. Forward proxies are when you're going from inside the corp out to random origin servers on the internet. In that case, the SSL cert would need to be served from the origin server, otherwise the client will think there's a man-in-the-middle attack going on This thread is talking about a reverse proxy scenario, where the ARR is routing requests to a fixed set of origin servers that are usually internal to the corporation.
In the reverse proxy scenario, it's a matter of configuring the correct SSL cert to be selected based upon the resource the client is requesting. You can create a separate https binding for each host with the required certificate, all on the default web site. Make sure to enable 'Require Server Name Identification' on the binding.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I have got a few web servers running and I want all of them to be accessible via one domain. I, however, need the source ip address to be kept when the requests are redirected to the servers. Otherwise, the servers see all the connections to be originated from localhost, which isn't very good.
You need a rewrite rule for each of your websites that are having traffic directed to them from the proxy server. Learn more. Ask Question.
Asked 6 years, 6 months ago. Active 7 months ago. Viewed 6k times. JohnnyLiao JohnnyLiao 2 2 gold badges 7 7 silver badges 17 17 bronze badges. Active Oldest Votes. Edited : You need a rewrite rule for each of your websites that are having traffic directed to them from the proxy server.
Tom Hall Tom Hall 3, 1 1 gold badge 20 20 silver badges 23 23 bronze badges. I have multiple servers. I'll come back with a solution in a moment. Otherwise you will get a server error when you add the rewrite rule.
You'll need to add each variable you want to set. Brock Hensley Brock Hensley 3, 2 2 gold badges 23 23 silver badges 44 44 bronze badges. Thank you for your sharing. Can it run in IIS 8? I cannot find any evidence that it does not.
Regolith 2, 9 9 gold badges 24 24 silver badges 37 37 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog.
Achieving High Availability and Scalability - ARR and NLB
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