Why We're #1

We recently commissioned a survey of FreeRADIUS users, in order to see how people are using the server. The survey was commissioned because RADIUS servers are usally hidden inside of private networks (for very good reasons), and are not publicly accessibly like HTTP or DNS servers. That is, Apache can say that it is the number one HTTP server in the Internet because of public results from Netcraft. In order to get the same data, we have to go ask site administrators what they are using.

The good news is that over 500 responses to the survey were received, with the results as of November 2006 summarized below.

Number of Users authenticated via FreeRADIUS

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 most interesting result is that there are a small percentage of sites have over 10,000,000 (that's 10 MILLION) users. When we add up all of the sites, 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!

Taking 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.

Number of Users
1 - 10 14%
11 - 100 17%
... - 10^3 25%
... - 10^4 25%
... - 10^5 13%
... - 10^6 4%
... - 10^7 < 1%
10^7 or more 1%

How many RADIUS servers are at each site

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.

Number of Servers
1 - 2 70%
3-5 19%
6-10 6%
11-20 2%
21 or more < 2%

Databases where user information is stored.

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.

Databases used
MySQL 32%
users file 22%
OpenLDAP 15%
Active Directory 13%
PostgreSQL 8%
Oracle 5%
Other < 4%

Authentication Protocols

Most sites are using RADIUS for 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.

Authentication Protocols
PAP, etc. 61%
Wireless (EAP) 35%
Digest (VOIP) 4%

Other RADIUS Servers

Not everyone uses FreeRADIUS, so we also asked what other RADIUS servers people have used.

As mentioned above, ACS and IAS have about an equal market share, and together account for about 50% of other servers. Another 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.

Other servers
Cisco ACS 24%
Microsoft IAS 23%
Cistron 12%
Funk 11%
OpenRADIUS 10%
Radiator 10%
Other 10%