Freeradius works well through authenticating users throught "files" option. In order to authenticate users throng "sql" , I have installed mysql 4.1.0 on the machine which has the Redhat 9 operation system. I followed the suggestion : mysql -uroot -prootpass radius < db_mysql.sql and made changes to radiusd.conf like below: authorise { preprocess chap mschap #counter #attr_filter #eap suffix sql #files #etc_smbpasswd } authenticate { authtype PAP { pap } authtype CHAP { chap } authtype MS-CHAP{ mschap } #pam #unix #authtype LDAP { # ldap #} } preacct { preprocess suffix #files } accounting { acct_unique detail #counter unix sql radutmp #sradutmp } session { radutmp } However when I input : radiusd -X, only got the following errors: Starting - reading configuration files ... reread_config: reading radiusd.conf Config: including file: /usr/local/etc/raddb/proxy.conf Config: including file: /usr/local/etc/raddb/clients.conf Config: including file: /usr/local/etc/raddb/snmp.conf Config: including file: /usr/local/etc/raddb/eap.conf Config: including file: /usr/local/etc/raddb/sql.conf main: prefix = "/usr/local" main: localstatedir = "/usr/local/var" main: logdir = "/usr/local/var/log/radius" main: libdir = "/usr/local/lib" main: radacctdir = "/usr/local/var/log/radius/radacct" main: hostname_lookups = no main: max_request_time = 30 main: cleanup_delay = 5 main: max_requests = 1024 main: delete_blocked_requests = 0 main: port = 0 main: allow_core_dumps = no main: log_stripped_names = no main: log_file = "/usr/local/var/log/radius/radius.log" main: log_auth = no main: log_auth_badpass = no main: log_auth_goodpass = no main: pidfile = "/usr/local/var/run/radiusd/radiusd.pid" main: user = "(null)" main: group = "(null)" main: usercollide = no main: lower_user = "no" main: lower_pass = "no" main: nospace_user = "no" main: nospace_pass = "no" main: checkrad = "/usr/local/sbin/checkrad" main: proxy_requests = yes proxy: retry_delay = 5 proxy: retry_count = 3 proxy: synchronous = no proxy: default_fallback = yes proxy: dead_time = 120 proxy: post_proxy_authorize = yes proxy: wake_all_if_all_dead = no security: max_attributes = 200 security: reject_delay = 1 security: status_server = no main: debug_level = 0 read_config_files: reading dictionary read_config_files: reading naslist Using deprecated naslist file. Support for this will go away soon. read_config_files: reading clients read_config_files: reading realms radiusd: entering modules setup Module: Library search path is /usr/local/lib Module: Loaded exec exec: wait = yes exec: program = "(null)" exec: input_pairs = "request" exec: output_pairs = "(null)" exec: packet_type = "(null)" rlm_exec: Wait=yes but no output defined. Did you mean output=none? Module: Instantiated exec (exec) Module: Loaded expr Module: Instantiated expr (expr) Module: Loaded PAP pap: encryption_scheme = "crypt" Module: Instantiated pap (pap) Module: Loaded CHAP Module: Instantiated chap (chap) Module: Loaded MS-CHAP mschap: use_mppe = yes mschap: require_encryption = no mschap: require_strong = no mschap: with_ntdomain_hack = no mschap: passwd = "(null)" mschap: authtype = "MS-CHAP" mschap: ntlm_auth = "(null)" Module: Instantiated mschap (mschap) Module: Loaded eap eap: default_eap_type = "md5" eap: timer_expire = 60 eap: ignore_unknown_eap_types = no eap: cisco_accounting_username_bug = no rlm_eap: Loaded and initialized type md5 rlm_eap: Loaded and initialized type leap gtc: challenge = "Password: " gtc: auth_type = "PAP" rlm_eap: Loaded and initialized type gtc mschapv2: with_ntdomain_hack = no rlm_eap: Loaded and initialized type mschapv2 Module: Instantiated eap (eap) Module: Loaded preprocess preprocess: huntgroups = "/usr/local/etc/raddb/huntgroups" preprocess: hints = "/usr/local/etc/raddb/hints" preprocess: with_ascend_hack = no preprocess: ascend_channels_per_line = 23 preprocess: with_ntdomain_hack = no preprocess: with_specialix_jetstream_hack = no preprocess: with_cisco_vsa_hack = no Module: Instantiated preprocess (preprocess) Module: Loaded realm realm: format = "suffix" realm: delimiter = "@" realm: ignore_default = no realm: ignore_null = no Module: Instantiated realm (suffix) Module: Loaded SQL sql: driver = "rlm_sql_mysql" sql: server = "localhost" sql: port = "" sql: login = "root" sql: password = "rootpass" sql: radius_db = "radius" sql: acct_table = "radacct" sql: acct_table2 = "radacct" sql: authcheck_table = "radcheck" sql: authreply_table = "radreply" sql: groupcheck_table = "radgroupcheck" sql: groupreply_table = "radgroupreply" sql: usergroup_table = "usergroup" sql: nas_table = "nas" sql: dict_table = "dictionary" sql: sqltrace = no sql: sqltracefile = "/usr/local/var/log/radius/sqltrace.sql" sql: readclients = no sql: deletestalesessions = yes sql: num_sql_socks = 5 sql: sql_user_name = "%{User-Name}" sql: default_user_profile = "" sql: query_on_not_found = no sql: authorize_check_query = "SELECT id, UserName, Attribute, Value, op FROM radcheck WHERE Username = '%{SQL-User-Name}' ORDER BY id" sql: authorize_reply_query = "SELECT id, UserName, Attribute, Value, op FROM radreply WHERE Username = '%{SQL-User-Name}' ORDER BY id" sql: authorize_group_check_query = "SELECT radgroupcheck.id,radgroupcheck.GroupName,radgroupcheck.Attribute,radgroupcheck.Value,radgroupcheck.op FROM radgroupcheck,usergroup WHERE usergroup.Username = '%{SQL-User-Name}' AND usergroup.GroupName = radgroupcheck.GroupName ORDER BY radgroupcheck.id" sql: authorize_group_reply_query = "SELECT radgroupreply.id,radgroupreply.GroupName,radgroupreply.Attribute,radgroupreply.Value,radgroupreply.op FROM radgroupreply,usergroup WHERE usergroup.Username = '%{SQL-User-Name}' AND usergroup.GroupName = radgroupreply.GroupName ORDER BY radgroupreply.id" sql: accounting_onoff_query = "UPDATE radacct SET AcctStopTime='%S', AcctSessionTime=unix_timestamp('%S') - unix_timestamp(AcctStartTime), AcctTerminateCause='%{Acct-Terminate-Cause}', AcctStopDelay = '%{Acct-Delay-Time}' WHERE AcctSessionTime=0 AND AcctStopTime=0 AND NASIPAddress= '%{NAS-IP-Address}' AND AcctStartTime <= '%S'" sql: accounting_update_query = "UPDATE radacct SET FramedIPAddress = '%{Framed-IP-Address}', AcctSessionTime = '%{Acct-Session-Time}', AcctInputOctets = '%{Acct-Input-Octets}', AcctOutputOctets = '%{Acct-Output-Octets}' WHERE AcctSessionId = '%{Acct-Session-Id}' AND UserName = '%{SQL-User-Name}' AND NASIPAddress= '%{NAS-IP-Address}'" sql: accounting_update_query_alt = "INSERT into radacct (AcctSessionId, AcctUniqueId, UserName, Realm, NASIPAddress, NASPortId, NASPortType, AcctStartTime, AcctSessionTime, AcctAuthentic, ConnectInfo_start, AcctInputOctets, AcctOutputOctets, CalledStationId, CallingStationId, ServiceType, FramedProtocol, FramedIPAddress, AcctStartDelay) values('%{Acct-Session-Id}', '%{Acct-Unique-Session-Id}', '%{SQL-User-Name}', '%{Realm}', '%{NAS-IP-Address}', '%{NAS-Port}', '%{NAS-Port-Type}', DATE_SUB('%S',INTERVAL (%{Acct-Session-Time:-0} + %{Acct-Delay-Time:-0}) SECOND), '%{Acct-Session-Time}', '%{Acct-Authentic}', '', '%{Acct-Input-Octets}', '%{Acct-Output-Octets}', '%{Called-Station-Id}', '%{Calling-Station-Id}', '%{Service-Type}', '%{Framed-Protocol}', '%{Framed-IP-Address}', '0')" sql: accounting_start_query = "INSERT into radacct (AcctSessionId, AcctUniqueId, UserName, Realm, NASIPAddress, NASPortId, NASPortType, AcctStartTime, AcctStopTime, AcctSessionTime, AcctAuthentic, ConnectInfo_start, ConnectInfo_stop, AcctInputOctets, AcctOutputOctets, CalledStationId, CallingStationId, AcctTerminateCause, ServiceType, FramedProtocol, FramedIPAddress, AcctStartDelay, AcctStopDelay) values('%{Acct-Session-Id}', '%{Acct-Unique-Session-Id}', '%{SQL-User-Name}', '%{Realm}', '%{NAS-IP-Address}', '%{NAS-Port}', '%{NAS-Port-Type}', '%S', '0', '0', '%{Acct-Authentic}', '%{Connect-Info}', '', '0', '0', '%{Called-Station-Id}', '%{Calling-Station-Id}', '', '%{Service-Type}', '%{Framed-Protocol}', '%{Framed-IP-Address}', '%{Acct-Delay-Time}', '0')" sql: accounting_start_query_alt = "UPDATE radacct SET AcctStartTime = '%S', AcctStartDelay = '%{Acct-Delay-Time}', ConnectInfo_start = '%{Connect-Info}' WHERE AcctSessionId = '%{Acct-Session-Id}' AND UserName = '%{SQL-User-Name}' AND NASIPAddress = '%{NAS-IP-Address}'" sql: accounting_stop_query = "UPDATE radacct SET AcctStopTime = '%S', AcctSessionTime = '%{Acct-Session-Time}', AcctInputOctets = '%{Acct-Input-Octets}', AcctOutputOctets = '%{Acct-Output-Octets}', AcctTerminateCause = '%{Acct-Terminate-Cause}', AcctStopDelay = '%{Acct-Delay-Time}', ConnectInfo_stop = '%{Connect-Info}' WHERE AcctSessionId = '%{Acct-Session-Id}' AND UserName = '%{SQL-User-Name}' AND NASIPAddress = '%{NAS-IP-Address}'" sql: accounting_stop_query_alt = "INSERT into radacct (AcctSessionId, AcctUniqueId, UserName, Realm, NASIPAddress, NASPortId, NASPortType, AcctStartTime, AcctStopTime, AcctSessionTime, AcctAuthentic, ConnectInfo_start, ConnectInfo_stop, AcctInputOctets, AcctOutputOctets, CalledStationId, CallingStationId, AcctTerminateCause, ServiceType, FramedProtocol, FramedIPAddress, AcctStartDelay, AcctStopDelay) values('%{Acct-Session-Id}', '%{Acct-Unique-Session-Id}', '%{SQL-User-Name}', '%{Realm}', '%{NAS-IP-Address}', '%{NAS-Port}', '%{NAS-Port-Type}', DATE_SUB('%S', INTERVAL (%{Acct-Session-Time:-0} + %{Acct-Delay-Time:-0}) SECOND), '%S', '%{Acct-Session-Time}', '%{Acct-Authentic}', '', '%{Connect-Info}', '%{Acct-Input-Octets}', '%{Acct-Output-Octets}', '%{Called-Station-Id}', '%{Calling-Station-Id}', '%{Acct-Terminate-Cause}', '%{Service-Type}', '%{Framed-Protocol}', '%{Framed-IP-Address}', '0', '%{Acct-Delay-Time}')" sql: group_membership_query = "SELECT GroupName FROM usergroup WHERE UserName='%{SQL-User-Name}'" sql: connect_failure_retry_delay = 60 sql: simul_count_query = "" sql: simul_verify_query = "SELECT RadAcctId, AcctSessionId, UserName, NASIPAddress, NASPortId, FramedIPAddress, CallingStationId, FramedProtocol FROM radacct WHERE UserName='%{SQL-User-Name}' AND AcctStopTime = 0" sql: postauth_table = "radpostauth" sql: postauth_query = "INSERT into radpostauth (id, user, pass, reply, date) values ('', '%{User-Name}', '%{User-Password:-Chap-Password}', '%{reply:Packet-Type}', NOW())" sql: safe-characters = "@abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.-_: /" rlm_sql (sql): Could not link driver rlm_sql_mysql: file not found rlm_sql (sql): Make sure it (and all its dependent libraries!) are in the search path of your system's ld. radiusd.conf[14]: sql: Module instantiation failed. Any suggestons?