ASP.Net core web servers: IIS Vs Kestrel Server Comparison and Why Both are Important

IIS Vs Kestrel Server

A web server is a program which allows HTTP to serve the files which form the web pages to the users, in response to their requests, which is allowed by their system’s HTTP clients. The web server of Kestrel is the latest type of web server that is given priority for the .NET application due to the fact that .Net community doesn’t have to worry about the compatibility for applications which are more than a decade old which was a big issue with IIS web server which is used as a web server for more than 15 years.

Reason for the kestrel web server to be built

The IIS web server is an old web server which has been in use for over 15 years by .Net community but the issue that came is that some applications which were built in that period were not compatible with recent technology and web services could not be used on them. Another issue was that as internet servers advanced the IIS web servers were not cope up to the speed of the internet servers making it slow, so a need for a faster web server became necessary. To do this, the .Net community used its set of previous information to create the most simple and quickest server ever possible and thus kestrel web server was born.

Advantages of kestrel web server over IIS web server

There are some advantages kestrel web server has over IIS web server. These are:-

  • It is faster as compared to the IIS web server.
  • It can be used with any operating system while IIS web server needed to be ported to the operating system except for if operating system was Windows or making .Net operate without the use of Internet Information Server.

Comparison of both the servers

The advantage that an IIS web server has over the Kestrel web server is that all kind of functionality as a user requires while kestrel web server while faster offers limited functionality making it more of an application server rather than a web server.

Feature-wise comparison among the two –

The feature comparison of IIS web server vs Kestrel web server is:-


  • Both have static files.
  • Both allow web application compression to some extent.


  • IIS web server only supports Windows while kestrel web server supports all platforms.
  • IIS web servers have HTTP access logs which is not the case in kestrel.
  • IIS allows port sharing/multiple apps running at the same time while kestrel doesn’t.
  • IIS has SSL certificates while kestrel only works with internal SSL traffic between the reverse proxy web servers and .Net.
  • IIS has windows authentication while kestrel doesn’t.
  • IIS has a management console which isn’t there in kestrel.
  • Process activation is there in case of IIS web servers while it isn’t there in kestrel.
  • IIS allows application initialization while kestrel doesn’t.
  • IIS has configuration API while kestrel doesn’t.
  • IIS allows request filters and limits while kestrel doesn’t.
  • IIS has IP and domain limitations while kestrel doesn’t.
  • IIS follows HTTP redirect rules while kestrel doesn’t.
  • IIS allows WebSocket protocol while kestrel allows middleware.
  • IIS does response output caching while kestrel doesn’t.
  • IIS has FTP servers while kestrel doesn’t.

The reason why we need both the servers

IIS web servers, as shown above, allows all functionality that a web server could provide while kestrel only allows limited functionality. This means if we need a lot of web services on our applications, then IIS web servers would be a better option. Another case where IIS web server would be the better option would be in case of old applications whose compatibility we know. Kestrel web server would be good in case of if we are working on a different platform such as Linux which would work better with Kestrel then with IIS. Another situation where we could use kestrel over IIS is if we need a faster web server. It is better for a user to have in case a situation as above happens he/she could follow accordingly.

IIS and kestrel has a lot of features and as mentioned above provides a lot of help in creating .net web applications through hire developer their features. A comparison of the two web servers also shows us how better a web server has become over the years as although kestrel allows limited functionality a lot of functionality that it doesn’t allow are ones which are not much needed in present web applications making it more useful. Another reason for why all functionality was not allowed in kestrel is that it would made the web server heavier while the goal was to make a lightweight web server and a faster one both of which would have been affected if more functionality was allowed.

One thought on “ASP.Net core web servers: IIS Vs Kestrel Server Comparison and Why Both are Important”

  1. Hеllo, Neat рօst. There’s an issue with your website in web explorer, could cһeck this? IE still is the market chief and a good portion of pеople ᴡill omit your great writing because of this problem.

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