RADIUS 是Remote Authentication Dial In User Service的縮寫，意思就是遠端用撥入驗證服務。 RADIUS是一個AAA協定，意思就是同時兼顧驗證(authentication)、 authorization及accounting三種服務的協定(protocol)，通常用於網路存取、或流動IP服務，適用於區域網及漫遊服務。
FreeRADIUS 是一個實現了 RADIUS 的伺服器。2012-09-10發布2.2.0 上個版本還是2011-09-30的2.1.12
改進：
Feature improvements100% configuration file compatible with 2.1.x. The only fix needed is to disallow "hashsize=0" for rlm_passwdUpdate Aruba, Alcatel Lucent, APC, BT, PaloAlto, Pureware, Redback, and Mikrotik dictionariesSwitch to using SHA1 for certificate digests instead of MD5. See raddb/certs/*.cnfAdded copyright statements to the dictionaries, so that we know when people are using them.Better documentation for radrelay and detail file writer. See raddb/modules/radrelay and raddb/radrelay.confAdded TLS-Cert-Subject-Alt-Name-Email from patch by Luke HowardAdded -F to radwhoAdded query timeouts to MySQL driver. Patch from Brian De Wolf.Add /etc/default/freeradius to debian package. Patch from Matthew NewtonFinalize DHCP and DHCP relay code. It should now work everywhere. See raddb/sites-available/dhcp, src_ipaddr and src_interface.DHCP capabilitiies are now compiled in by default. It runs as a DHCP server ONLY when manually enabled.Added one letter expansions: %G - request minute and %I request ID.Added script to convert ISC DHCP lease files to SQL pools. See scripts/isc2ippool.plAdded rlm_cache to cache arbitrary attributes.Added max_use to rlm_ldap to force connection to be re-established after a given number of queries.Added configtest option to Debian init scripts, and automatic config test on restart.Added cache config item to rlm_krb5. When set to "no" ticket caching is disabled which may increase performance.Bug fixesFix CVE-2012-3547. All users of 2.1.10, 2.1.11, 2.1.12, and 802.1X should upgrade immediately.Fix typo in detail file writer, to skip writing if the packet was read from this detail file.Free cached replies when closing resumed SSL sessions.Fix a number of issues found by Coverity.Fix memory leak and race condition in the EAP-TLS session cache. Thanks to Phil Mayers for tracking down OpenSSL APIs.Restrict ATTRIBUTE names to character sets that make sense.Fix EAP-TLS session Id length so that OpenSSL doesn't get excited.Fix SQL IPPool logic for non-timer attributes. Closes bug #181Change some informational messages to DEBUG rather than error.Portability fixes for FreeBSD. Closes bug #177A much better fix for the _lt__PROGRAM__LTX_preloaded_symbols nonsense.Safely handle extremely long lines in conf file variable expansionFix for Debian bug #606450Mutex lock around rlm_perl Clone routines. Patch from Eike DehlingThe passwd module no longer permits "hashsize = 0". Setting that is pointless for a host of reasons. It will also break the server.Fix proxied inner-tunnel packets sometimes having zero authentication vector. Found by Brian Julin.Added $(EXEEXT) to Makefiles for portability. Closes bug #188.Fix minor build issue which would cause rlm_eap to be built twice.When using "status_check=request" for a home server, the username and password must be specified, or the server will not start.EAP-SIM now calculates keys from the SIM identity, not from the EAP-Identity. Changing the EAP type via NAK may result in identities changing. Bug reported by Microsoft EAP team.Use home server src_ipaddr when sending Status-Server packetsDecrypt encrypted ERX attributes in CoA packets.Fix registration of internal xlat's so %{mschap:...} doesn't disappear after a HUP.Can now reference tagged attributes in expansions. e.g. %{Tunnel-Type:1} and %{Tunnel-Type:1[0]} now work.Correct calculation of Message-Authenticator for CoA and Disconnect replies. Patch from Jouni MalinenInstall rad_counter, for managing rlm_counter files.Add unique index constraint to all SQL flavours so that alternate queries work correctly.The TTLS diameter decoder is now more lenient. It ignores unknown attributes, instead of rejecting the TTLS session.Use "globfree" in detail file reader. Prevents very slow leak. Closes bug #207.Operator =~ shouldn't copy the attribute, like :=. It should instead behave more like ==.Build main Debian package without SQL dependenciesUse max_queue_size in threading codeUpdate permissions in raddb/sql/postgresql/admin.sqlAdded OpenSSL_add_all_algorithms() to fix issues where OpenSSL wouldn't use methods it knew about.Add more sanity checks in dynamic_clients code so the server won't crash if it attempts to load a badly formated client definition.下載：ftp://ftp.freeradius.org/pub/freeradius/freeradius-server-2.2.0.tar.bz2