Most sites using FreeRADIUS are intermediate in size, and are probably running the server in enterprise (i.e. corporate) environments, or in small ISPs. Over 90% of the sites have less than 100,000 users.

The interesting data point, though, is that there are a small percentage of sites have over 10,000,000 (10 MILLION) users. When we add up the numbers, the total comes to about 100,000,000 users who are authenticated via FreeRADIUS. And that number includes only the sites that filled out the survey!

When we take into account the other results, our best estimate is that FreeRADIUS is responsible for authenticating at least one third of the users on the Internet. The rest of the users are split into two roughly equal parts: Cisco ACS and Microsoft IAS (each with an equal share); and all of the other RADIUS servers combined.

Not surprisingly, most sites have a very small number of servers. A few sites (likely the biggest ones) have a large number of servers.

It looks like most sites under 10000 users have one or two servers. As the number of users grows, so does the number of servers used. A few sites have more than 50 servers, likely because they are placing servers at multiple locations.

Taken together the various SQL modules account for nearly 50% of deployments. The only surprise is that Active Directory has such a low ranking, as it is the database used in most internal corporate (i.e. enterprise) environments. The conclusion that we can reach from this is that the people filling out this survey are probably ISP's and resellers rather than enterprise IT administrators.

Another conclusion is that if you have to store a few million users in a database, Active Directory probably isn't your first choice.

Most sites are using RADIUS for normal dial-in user authentication. e.g. Telephone dial-up, ADSL, etc. The number of wireless deployments is large, though, at just over a third. We expect that there will be more new wireless deployments in the future.

While we haven't broken the numbers out here, PEAP, EAP-TLS, and EAP-TTLS all have about the same share of the wireless space. That is an interesting statistic, because

Not everyone uses FreeRADIUS, so we asked which other RADIUS servers sites have used in the past.

As mentioned above, ACS and IAS have about an equal market share, and together account for about 50% of other servers. Anther 40% is shared pretty much equally between a few well-known RADIUS servers. The last 10% is a jumble of old servers (some very old), or servers that are targetted towards niche markets.

The numbers for Funk and Radiator are probably too low, because the survey was focussed on sites that have chosen to deploy Open Source. For the same reasons mentioned before, we expect that enterprises who have chosen to use a commercial product have also not filled out the survey.