Google Servers used by different services as they are returned in the HTTP headers. Not all of them have transparent names and some of them may suggest interesting data (like the ctcserver for the not-yet-existent Google Call service linked from Google robots.txt). Google Web Server is a modified version of Apache custom server that runs on Linux.
Google System
| Server Name | Services |
| GWS (Google Web Server) | Web Search, Image Search and many other services |
| GFE/1.3 (Google Front-End) | Gmail, Calendar, Picasa Web Albums, Docs, Blogger, orkut, Reader and many other services |
| GWS-GRFE/0.50 | Groups |
| bsfe (Blog Search Front-End) | Blog Search |
| OFE/0.1 (Ocean Front-End) | Book Search, Patent Search, Catalogs (Ocean is Google Book Search code-name) |
| SMS search frontend 1.0 | Google SMS |
| Search-History HTTP Server | Web History |
| Auto-Completion Server | Google Suggest, Firefox/Google Toolbar auto-complete |
| TrustRank Frontend | Safe Browsing |
| GCS/1.0 | Safe Browsing |
| SFE/0.8 | Finance |
| FTS (C)1997-2007 Interactive Data Managed Solutions AG | Finance charts |
| asfe | Base |
| mediaserver | Base (images) |
| cffe | Product Search (Froogle) |
| btfe | Thumbnails: Image Search, Google Video, Youtube |
| Video Stats Server | Google Video |
| cachefe:image (Cache Front-End) | Picasa Web photos |
| staticfe | interface images (Picasa Web) |
| ctcserver | Google Call ( www.google.com/call ) |
| GoogleChartServer/1.0 | used for dynamically-generated charts (e.g.: Google Video stats) |
| NFE/1.0 (News Front-End) | News |
| mfe (Maps Front-End) | Maps |
| Keyhole Server 2.4 | Maps, Earth (imagery) |
| PSFE/4.0 | Alerts |
| igfe (iGoogle Front-End) | iGoogle |
| COMINST/1.0 | Testing software installation (Pack, Picasa) |
| TWS/0.9 (Translation Web Server) | Translate |
| mws (Music Web Server) | Music Search |
| R2FE/1.0 (Reviews Front-End) | Reviews (Music, Movies) |
| zfe | Reviews |
| pfe | Co-op |
| codesite/5477219 | Code |
| ga-reporting-fe | Analytics reporting |
| ucfe | Analytics |
| lpfe | Analytics (www.google-analytics.com/siteopt.js) |
| Toolbar Gaia User Service Server | Google Toolbar authentication |
| cafe (Ad Conversion Front-End) | Conversions |
| AdClickServer | Google test ad server |
| Google Trends | Google Trends |
| TFE/0.0 (Transliteration Front-End) | Google Indic Transliteration |
| Apache | most Labs services |
Google System
