Web server surveys have been around for a long time. One of the problems with running a survey is how to produce meaningful results given the number of choices with the collection and reporting methodologies. Some examples:

• How does one treat wildcarded DNS sites that generate unlimited number of unique hostnames, all residing on the same system?
• How does one treat taste-testing web sites that do not have any unique content on them at all?
• If very large number of web sites reside on a single IP address, is it a a case of search engine spamming, a large number of low traffic web sites on a single platform, or a web hosting facility using load-redirection for a large number of legitimate web sites?
• How "greedy" or aggressive should the hunt for new web sites be?

This particular report addresses this in part by counting unique IP addresses in an attempt at answering the question of how many installations of a particular server might exist. By using the IP address as a proxy for the physical hardware on which a server is running, we still need to be aware that it is not a perfect 1 to 1 mapping:

• A load balanced network of servers might share a single public facing IP address, and be undercounted.
• A single server may have multiple public IP addresses bound to one or more network cards on the system, and thus still be counted more than once.

While not a perfect solution, we feel that counting web servers by IP will give a much closer view of the number of server installs for a given technology.

Click any server to see detailed graphs and histories.

Server	February 2001 Count	February 2001 %	January 2001 Count	January 2001 %	Growth %
Apache	594,720	46.83	590,064	46.72	0.25
Microsoft-IIS	429,463	33.82	425,118	33.66	0.48
Netscape-Enterprise	40,804	3.21	41,225	3.26	-1.55
thttpd	39,596	3.12	40,205	3.18	-2.04
Rapidsite	37,266	2.93	36,232	2.87	2.30
null	17,712	1.39	17,605	1.39	0.07
WebSitePro	11,837	0.93	12,097	0.96	-2.67
Lotus-Domino	10,301	0.81	10,250	0.81	-0.04
Stronghold	8,813	0.69	8,893	0.70	-1.43
WebSTAR	8,741	0.69	8,699	0.69	-0.05
WN	5,623	0.44	5,778	0.46	-3.20
NCSA	5,599	0.44	5,784	0.46	-3.72
Netscape-FastTrack	5,570	0.44	5,894	0.47	-6.00
BESTWWWD	4,934	0.39	4,926	0.39	-0.37
Zeus	3,336	0.26	3,230	0.26	2.73
Roxen·Challenger	2,249	0.18	2,492	0.20	-10.23
CERN	1,887	0.15	1,923	0.15	-2.40
Apache-1.3.4	1,887	0.15	2,889	0.23	-35.03
Netscape-Communications	1,651	0.13	1,769	0.14	-7.17
AppleShareIP	1,512	0.12	1,458	0.12	3.15
Apache-AdvancedExtranetServer	1,424	0.11	1,348	0.11	5.07
NetWare-Enterprise-Web-Server	1,252	0.10	1,143	0.09	8.95
FileMakerPro	1,175	0.09	1,195	0.09	-2.20
Red	1,087	0.09	1,222	0.10	-11.52
Oracle_Web_Listener	1,083	0.09	1,075	0.09	0.21
Novell-HTTP-Server	1,031	0.08	1,067	0.08	-3.89
Netscape-Commerce	978	0.08	1,036	0.08	-6.10
HPWB	918	0.07	921	0.07	-0.86
ApacheFP	864	0.07	850	0.07	1.10
IBM_HTTP_Server	839	0.07	777	0.06	7.40
mod_perl	832	0.07	864	0.07	-4.22
OSU	818	0.06	820	0.06	-0.78
WebSite	810	0.06	851	0.07	-5.33
IBM-HTTP-Server	758	0.06	731	0.06	3.14
Domino-Go-Webserver	706	0.06	712	0.06	-1.37
Ipswitch-IMail	682	0.05	635	0.05	6.83
Affinity-Apache	627	0.05	632	0.05	-1.32
FirstClass	604	0.05	596	0.05	0.80
IdeaWebServer	501	0.04	479	0.04	4.03
NaviServer	491	0.04	508	0.04	-3.86
Xitami	451	0.04	458	0.04	-2.05
SAMBAR	440	0.03	436	0.03	0.38
QuidProQuo	429	0.03	452	0.04	-5.60
Commerce-Builder	423	0.03	440	0.03	-4.38
MacHTTP	404	0.03	418	0.03	-3.87
JavaWebServer	391	0.03	416	0.03	-6.51
SWS-1.0	390	0.03	407	0.03	-4.69
Purveyor	385	0.03	392	0.03	-2.31
Microsoft-PWS	374	0.03	395	0.03	-5.82
ApacheSSL	369	0.03	370	0.03	-0.80
Lasso	367	0.03	350	0.03	4.30
Microsoft-PWS-95	363	0.03	359	0.03	0.57
Roxen	330	0.03	257	0.02	27.72
Squid	319	0.03	313	0.02	1.37
Worldgroup	300	0.02	307	0.02	-2.80
Ultraseek	295	0.02	291	0.02	0.83
MACOS_Personal_Websharing	293	0.02	295	0.02	-1.21
Microsoft-Internet-Information-Server	292	0.02	325	0.03	-10.63
OmniHTTPd	278	0.02	274	0.02	0.92
IBM-ICS	242	0.02	251	0.02	-4.10
Sun_WebServer	232	0.02	226	0.02	2.11
Statistics	232	0.02	230	0.02	0.33
Caudium	222	0.02	0	0.00	N/A
Oracle_Web_listener3.0.2.0.0	221	0.02	228	0.02	-3.59
WebLogic	209	0.02	195	0.02	6.61
Open-Market-Secure-WebServer	192	0.02	200	0.02	-4.51
Zope	186	0.01	175	0.01	5.72
Powered	173	0.01	175	0.01	-1.67
eShare-Expressions	171	0.01	168	0.01	1.24
Web_Server_4D	166	0.01	166	0.01	-0.53
FrontPage-PWS32	159	0.01	163	0.01	-2.97
Web	154	0.01	150	0.01	2.12
PowerWeb	151	0.01	155	0.01	-3.10
ConcentricHost-Ashurbanipal	150	0.01	159	0.01	-6.16
Apache-SSL-US	147	0.01	146	0.01	0.15
AiNET	147	0.01	205	0.02	-28.68
AnWeb	143	0.01	147	0.01	-3.24
Oracle_Web_listener2.1	131	0.01	137	0.01	-4.89
Mini-Proxy	131	0.01	120	0.01	8.58
IgServ	123	0.01	131	0.01	-6.61
AOLserver	122	0.01	102	0.01	18.97
Unknown	120	0.01	115	0.01	3.79
CommerceServer400	118	0.01	119	0.01	-1.37
David-WebBox	108	0.01	107	0.01	0.40
IBM	107	0.01	106	0.01	0.40
SilverStream	104	0.01	97	0.01	6.64
NetPresenz	104	0.01	107	0.01	-3.32
CommuniGatePro	103	0.01	100	0.01	2.45
Oracle_Web_Listener_NT_2.1.0.3.1	98	0.01	103	0.01	-5.36
Q100	96	0.01	95	0.01	0.51
ALEPH	93	0.01	85	0.01	8.83
Lotus	91	0.01	95	0.01	-4.72
HTTPS	91	0.01	96	0.01	-5.71
MGI	88	0.01	86	0.01	1.78
Apache-1.3.12	87	0.01	85	0.01	1.81
UserLand	84	0.01	83	0.01	0.66
HTTP	80	0.01	83	0.01	-4.13
Oracle_Web_listener3.0	79	0.01	110	0.01	-28.57
AppleWSE	79	0.01	77	0.01	2.05
Cougar	78	0.01	0	0.00	N/A

Note: Readers are cautioned that the Growth percentages are based on a server's market share penetration rather than the absolute number of servers we detected. Thus, it is possible for the number of servers to increase, while the growth is actually a negative value.