When comparing Lighttpd vs IIS, the Slant community recommends Lighttpd for most people. In the question“What are the best web servers?” Lighttpd is ranked 3rd while IIS is ranked 13th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Simple setup for static content
Pro Fast and built for scalability
Lighttpd is event-driven, asynchronous, non-blocking and single threaded. This allows lighttpd to be manage resources more efficiently compared to thread-based models (like Apache).
Pro Highly efficient memory use
With a small memory footprint compared to other web-servers, effective management of the cpu-load.
Pro Free and open source
Pro Lightweight
Lighttpd offers a more basic set of functions out of the box compared most web servers. Extra functionality can be added via modules.
Pro Quite easy to setup and configure

Pro PHP spport
PHP applications can be run using IIS. Simple to install and configure.
Pro .NET and ASPX script support
Pro Supported by Microsoft
Pro Authentication (Anonymous, Basic, Digest, Integrated Windows Auth, UNC, .NET Passport (<6), Certificate)
Pro IPv6 support (IIS 6+)
Pro Multiple websites can be run on 1 server
Pro HTTP/2, HTTP/2, HTTPS, FTP, FTPS, SMTP and NNTP support
Pro Runs on literal NT 3.51
So you can boot up that ancient work computer and get IIS (Free addon at the time) for that computer
Pro Very fast
If you want a quick web server, use this, because i mean like, on my laptop, the first request is 1 or 2 seconds, after that, it becomes a split second!
Pro In-depth diagnostic tools
Cons
Con 1 website limit per server (also pre-7.0 client os limit)
Con 10 simultaneous connection limit on versions before 7.0 on client operating systems
Con Only runs on Windows
This Microsoft-proprietary web server software, can only run in the Windows operating systems for full support of it and all of its features. It is not capable of being run in a non-Windows environment without sacrificing some functionality and of course the support.
Con Proprietary
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