Apache HTTP Server and Microsoft IIS (Internet Information Services) are two of the world's most popular web servers.
Comparison chart
 | Apache | IIS |
|---|---|---|
| Basic access authentication | Yes | Yes |
| Digest access authentication | Yes | Yes |
| HTTPS support | Yes | Yes |
| Virtual hosting | Yes | Yes |
| CGI support | Yes | Yes |
| Cost | Free | Bundled with Windows NT family products |
| FastCGI support | Yes | Yes |
| Servlets | No | No |
| SSI support | Yes | Yes |
| ASP.Net support | Yes (via "mod_aspdotnet" module) | Yes |
| Runs in user or kernel space | user space | kernel or user space |
| Administration console | Yes | Yes |
| IPv6 | Yes | Yes |
| Developed by | Apache Software Foundation | Microsoft Corp. |
| Initial Release | 1995 | With Windows NT 3.51 |
| Latest Release | 2.4.7 (released 2012-11-25) | 8.5 |
| Portable configuration | Yes text/file | Yes (Import & Export ) binary |
| Operating Systems supported | Cross-platform (Windows, Mac OS X, Linux, BSD, Solaris, eCS, OpenVMS, AIX, z/OS) | Windows |
| License | Apache License 2.0 | Proprietary |
| Website | http://httpd.apache.org/ | http://www.microsoft.com/iis |
Application Server
Comments: Apache vs IIS