posixAccount,posixGroup, and CiscoAVPair
Hi, here is my problem: 0) Cisco APs - Radius - Ldap authentication via 802.1x - PEAP - MSCHAPv2 works. 1) I need to link the group of the user that try to authenticate with the SSID, so i can allow only a particular group of users to use a particular SSID/VLAN. 2) I have an OpenLDAP backend were all users and groups reside. users have, among others, objectClass posixAccount and sambaSamAccount. Groups have shadowAccount. 3) I DO NOT HAVE LDAPv3 SCHEMA FOR RADIUS ATTRIBUTES, so no objectClass radiusprofile for users. 4) A typical entry for user (relevant attributes): uid=username,ou=People,dc=mydomain,dc=it uid=<username> gidNumber=<gid> .. 5) A typical group entry (relevant attributes): cn=groupname, dc=mydomain,dc=it cn=<groupname> gidNumber=<gid> memberUid=<list of usernames> ... 6) I nave Cisco APs as NAS, with which i am able to send the SSID info, using vsa, to the radius server. From the request list I see: User-Name = "username" Framed-MTU = 1400 Called-Station-Id = "xxxx.xxxx.xxxx" Calling-Station-Id = "yyyy.yyyy.yyyy" Cisco-AVPair = "ssid=ZZZZ" Service-Type = Login-User Message-Authenticator = 0x8bded00fdb8decb62a26bc9c01f33938 EAP-Message = 0x02....... NAS-Port-Type = Wireless-802.11 Cisco-NAS-Port = "260" NAS-Port = 260 NAS-IP-Address = nnn.nnn.nnn.nnn NAS-Identifier = "apname" 7) I really connot figure out a correct configuration of: * ldap module in radius.conf * selection in users * mapping of group attribute in ldap.attrmap I try: (radius.conf, module ldap) filter = "(&(objectClass=posixAccount)(uid=%{Stripped-User-Name:-%{User-Name}}))" groupname_attribute=gidNumber groupmembership_filter = "(&(objectClass=posixGroup)(memberUid=%{Stripped-User-Name:-%{User-Name}))" groupmembership_attribute = gidNumber compare_check_items = yes (if i do not set this, all users with valid credentials can log in!) (users) DEFAULT Cisco-AVPair=="ssid=SISSA-STAFF", Ldap-Group==800 Fall-Through = no DEFAULT Cisco-AVPair=="ssid=SISSA-SIS", Ldap-Group==801 Fall-Through = no Here is the 'radiusd -X' output: ---------------------------- Starting - reading configuration files ... reread_config: reading radiusd.conf Config: including file: /etc/raddb/proxy.conf Config: including file: /etc/raddb/clients.conf Config: including file: /etc/raddb/snmp.conf Config: including file: /etc/raddb/eap.conf Config: including file: /etc/raddb/ldap.conf main: prefix = "/usr" main: localstatedir = "/var" main: logdir = "/var/log/radius" main: libdir = "/usr/lib" main: radacctdir = "/var/log/radius/radacct" main: hostname_lookups = no main: snmp = 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 = "/var/log/radius/radius.log" main: log_auth = no main: log_auth_badpass = no main: log_auth_goodpass = no main: pidfile = "/var/run/radiusd/radiusd.pid" main: user = "radiusd" main: group = "radiusd" main: usercollide = no main: lower_user = "no" main: lower_pass = "no" main: nospace_user = "no" main: nospace_pass = "no" main: checkrad = "/usr/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 = no 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/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 = "md5" 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: ntlm_auth = "(null)" Module: Instantiated mschap (mschap) Module: Loaded System unix: cache = no unix: passwd = "(null)" unix: shadow = "/etc/shadow" unix: group = "(null)" unix: radwtmp = "/var/log/radius/radwtmp" unix: usegroup = no unix: cache_reload = 600 Module: Instantiated unix (unix) Module: Loaded LDAP ldap: server = "ldapserver.mydomain.it" ldap: port = 389 ldap: net_timeout = 1 ldap: timeout = 4 ldap: timelimit = 3 ldap: identity = "cn=Reader,dc=sissa,dc=it" ldap: tls_mode = no ldap: start_tls = no ldap: tls_cacertfile = "(null)" ldap: tls_cacertdir = "(null)" ldap: tls_certfile = "(null)" ldap: tls_keyfile = "(null)" ldap: tls_randfile = "(null)" ldap: tls_require_cert = "allow" ldap: password = "cippalippa1" ldap: basedn = "dc=mydomain,dc=it" ldap: filter = "(&(objectClass=posixAccount)(uid=%{Stripped-User-Name:-%{User-Name}}))" ldap: base_filter = "(objectclass=radiusprofile)" ldap: default_profile = "(null)" ldap: profile_attribute = "(null)" ldap: password_header = "(null)" ldap: password_attribute = "(null)" ldap: access_attr = "(null)" ldap: groupname_attribute = "gidNumber" ldap: groupmembership_filter = "(&(objectClass=posixGroup)(memberUid=%{Stripped-User-Name:-%{User-Name}))" ldap: groupmembership_attribute = "gidNumber" ldap: dictionary_mapping = "/etc/raddb/ldap.attrmap" ldap: ldap_debug = 0 ldap: ldap_connections_number = 5 ldap: compare_check_items = yes ldap: access_attr_used_for_allow = yes ldap: do_xlat = yes ldap: set_auth_type = yes rlm_ldap: Registering ldap_groupcmp for Ldap-Group rlm_ldap: Registering ldap_xlat with xlat_name ldap rlm_ldap: reading ldap<->radius mappings from file /etc/raddb/ldap.attrmap rlm_ldap: LDAP radiusCheckItem mapped to RADIUS $GENERIC$ rlm_ldap: LDAP radiusReplyItem mapped to RADIUS $GENERIC$ rlm_ldap: LDAP radiusAuthType mapped to RADIUS Auth-Type rlm_ldap: LDAP radiusSimultaneousUse mapped to RADIUS Simultaneous-Use rlm_ldap: LDAP radiusCalledStationId mapped to RADIUS Called-Station-Id rlm_ldap: LDAP radiusCallingStationId mapped to RADIUS Calling-Station-Id rlm_ldap: LDAP sambaLMPassword mapped to RADIUS LM-Password rlm_ldap: LDAP sambaNTPassword mapped to RADIUS NT-Password rlm_ldap: LDAP sambaAcctFlags mapped to RADIUS SMB-Account-CTRL-TEXT rlm_ldap: LDAP radiusExpiration mapped to RADIUS Expiration rlm_ldap: LDAP radiusNASIpAddress mapped to RADIUS NAS-IP-Address rlm_ldap: LDAP radiusServiceType mapped to RADIUS Service-Type rlm_ldap: LDAP radiusFramedProtocol mapped to RADIUS Framed-Protocol rlm_ldap: LDAP radiusFramedIPAddress mapped to RADIUS Framed-IP-Address rlm_ldap: LDAP radiusFramedIPNetmask mapped to RADIUS Framed-IP-Netmask rlm_ldap: LDAP radiusFramedRoute mapped to RADIUS Framed-Route rlm_ldap: LDAP radiusFramedRouting mapped to RADIUS Framed-Routing rlm_ldap: LDAP radiusFilterId mapped to RADIUS Filter-Id rlm_ldap: LDAP radiusFramedMTU mapped to RADIUS Framed-MTU rlm_ldap: LDAP radiusFramedCompression mapped to RADIUS Framed-Compression rlm_ldap: LDAP radiusLoginIPHost mapped to RADIUS Login-IP-Host rlm_ldap: LDAP radiusLoginService mapped to RADIUS Login-Service rlm_ldap: LDAP radiusLoginTCPPort mapped to RADIUS Login-TCP-Port rlm_ldap: LDAP radiusCallbackNumber mapped to RADIUS Callback-Number rlm_ldap: LDAP radiusCallbackId mapped to RADIUS Callback-Id rlm_ldap: LDAP radiusFramedIPXNetwork mapped to RADIUS Framed-IPX-Network rlm_ldap: LDAP radiusClass mapped to RADIUS Class rlm_ldap: LDAP radiusSessionTimeout mapped to RADIUS Session-Timeout rlm_ldap: LDAP radiusIdleTimeout mapped to RADIUS Idle-Timeout rlm_ldap: LDAP radiusTerminationAction mapped to RADIUS Termination-Action rlm_ldap: LDAP radiusLoginLATService mapped to RADIUS Login-LAT-Service rlm_ldap: LDAP radiusLoginLATNode mapped to RADIUS Login-LAT-Node rlm_ldap: LDAP radiusLoginLATGroup mapped to RADIUS Login-LAT-Group rlm_ldap: LDAP radiusFramedAppleTalkLink mapped to RADIUS Framed-AppleTalk-Link rlm_ldap: LDAP radiusFramedAppleTalkNetwork mapped to RADIUS Framed-AppleTalk-Network rlm_ldap: LDAP radiusFramedAppleTalkZone mapped to RADIUS Framed-AppleTalk-Zone rlm_ldap: LDAP radiusPortLimit mapped to RADIUS Port-Limit rlm_ldap: LDAP radiusLoginLATPort mapped to RADIUS Login-LAT-Port rlm_ldap: LDAP radiusReplyMessage mapped to RADIUS Reply-Message conns: 0x9561bc8 Module: Instantiated ldap (ldap) Module: Loaded eap eap: default_eap_type = "peap" 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 tls: rsa_key_exchange = no tls: dh_key_exchange = yes tls: rsa_key_length = 512 tls: dh_key_length = 512 tls: verify_depth = 0 tls: CA_path = "(null)" tls: pem_file_type = yes tls: private_key_file = "/etc/raddb/certs/mydomain-certs/key.pem" tls: certificate_file = "/etc/raddb/certs/mydomain-certs/crt.pem" tls: CA_file = "/etc/raddb/certs/mydomain-certs/mydomain-ca.pem" tls: private_key_password = "(null)" tls: dh_file = "/etc/raddb/certs/dh" tls: random_file = "/etc/raddb/certs/random" tls: fragment_size = 1024 tls: include_length = yes tls: check_crl = no tls: check_cert_cn = "(null)" tls: cipher_list = "(null)" tls: check_cert_issuer = "(null)" rlm_eap_tls: Loading the certificate file as a chain rlm_eap: Loaded and initialized type tls ttls: default_eap_type = "md5" ttls: copy_request_to_tunnel = no ttls: use_tunneled_reply = no rlm_eap: Loaded and initialized type ttls peap: default_eap_type = "mschapv2" peap: copy_request_to_tunnel = yes peap: use_tunneled_reply = no peap: proxy_tunneled_request_as_eap = yes rlm_eap: Loaded and initialized type peap mschapv2: with_ntdomain_hack = no rlm_eap: Loaded and initialized type mschapv2 Module: Instantiated eap (eap) Module: Loaded preprocess preprocess: huntgroups = "/etc/raddb/huntgroups" preprocess: hints = "/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 preprocess: with_alvarion_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 files files: usersfile = "/etc/raddb/users" files: acctusersfile = "/etc/raddb/acct_users" files: preproxy_usersfile = "/etc/raddb/preproxy_users" files: compat = "no" Module: Instantiated files (files) Module: Loaded Acct-Unique-Session-Id acct_unique: key = "User-Name, Acct-Session-Id, NAS-IP-Address, Client-IP-Address, NAS-Port" Module: Instantiated acct_unique (acct_unique) Module: Loaded detail detail: detailfile = "/var/log/radius/radacct/%{Client-IP-Address}/detail-%Y%m%d" detail: detailperm = 384 detail: dirperm = 493 detail: locking = no Module: Instantiated detail (detail) Module: Loaded radutmp radutmp: filename = "/var/log/radius/radutmp" radutmp: username = "%{User-Name}" radutmp: case_sensitive = yes radutmp: check_with_nas = yes radutmp: perm = 384 radutmp: callerid = yes Module: Instantiated radutmp (radutmp) Listening on authentication *:1812 Listening on accounting *:1813 Ready to process requests. rad_recv: Access-Request packet from host xxx.xxx.xxx.xxx:1645, id=181, length=165 User-Name = "test" Framed-MTU = 1400 Called-Station-Id = "001b.2b6a.dbd0" Calling-Station-Id = "000d.889c.8b70" Cisco-AVPair = "ssid=SISSA-SIS" Service-Type = Login-User Message-Authenticator = 0x4e756588125d03a06da9a2bc7acf6ede EAP-Message = 0x0202000801616365 NAS-Port-Type = Wireless-802.11 Cisco-NAS-Port = "290" NAS-Port = 290 NAS-IP-Address = xxx.xxx.xxx.xxx NAS-Identifier = "ciscoap" Processing the authorize section of radiusd.conf modcall: entering group authorize for request 0 modcall[authorize]: module "preprocess" returns ok for request 0 modcall[authorize]: module "chap" returns noop for request 0 modcall[authorize]: module "mschap" returns noop for request 0 rlm_realm: No '@' in User-Name = "test", looking up realm NULL rlm_realm: No such realm "NULL" modcall[authorize]: module "suffix" returns noop for request 0 rlm_eap: EAP packet type response id 2 length 8 rlm_eap: No EAP Start, assuming it's an on-going EAP conversation modcall[authorize]: module "eap" returns updated for request 0 rlm_ldap: Entering ldap_groupcmp() radius_xlat: 'dc=mydomain,dc=it' radius_xlat: '(&(objectClass=posixAccount)(uid=test))' rlm_ldap: ldap_get_conn: Checking Id: 0 rlm_ldap: ldap_get_conn: Got Id: 0 rlm_ldap: attempting LDAP reconnection rlm_ldap: (re)connect to auth-01.mydomain.it:389, authentication 0 rlm_ldap: could not set LDAP_OPT_X_TLS_REQUIRE_CERT option to allow rlm_ldap: bind as cn=user,dc=mydomain,dc=it/password to ldapserver.mydomain.it:389 rlm_ldap: waiting for bind result ... rlm_ldap: Bind was successful rlm_ldap: performing search in dc=mydomain,dc=it, with filter (&(objectClass=posixAccount)(uid=test)) rlm_ldap: ldap_release_conn: Release Id: 0 radius_xlat: '(&(objectClass=posixGroup)(memberUid=test))' rlm_ldap: ldap_get_conn: Checking Id: 0 rlm_ldap: ldap_get_conn: Got Id: 0 rlm_ldap: performing search in dc=mydomain,dc=it, with filter (&(gidNumber=801)(&(objectClass=posixGroup)(memberUid=test))) rlm_ldap::ldap_groupcmp: User found in group 801 rlm_ldap: ldap_release_conn: Release Id: 0 users: Matched entry DEFAULT at line 4 modcall[authorize]: module "files" returns ok for request 0 rlm_ldap: - authorize rlm_ldap: performing user authorization for test radius_xlat: '(&(objectClass=posixAccount)(uid=test))' radius_xlat: 'dc=mydomain,dc=it' rlm_ldap: ldap_get_conn: Checking Id: 0 rlm_ldap: ldap_get_conn: Got Id: 0 rlm_ldap: performing search in dc=mydomain,dc=it, with filter (&(objectClass=posixAccount)(uid=test)) rlm_ldap: looking for check items in directory... rlm_ldap: Adding sambaAcctFlags as SMB-Account-CTRL-TEXT, value [U] & op=21 rlm_ldap: Adding sambaNTPassword as NT-Password, value xxxxxxxxxxxxxxxxxxxxxxxx & op=21 rlm_ldap: Adding sambaLMPassword as LM-Password, value xxxxxxxxxxxxxxxxxxxxxxxxxx & op=21 rlm_ldap: looking for reply items in directory... rlm_ldap: Entering ldap_groupcmp() radius_xlat: 'dc=mydomain,dc=it' radius_xlat: '(&(objectClass=posixGroup)(memberUid=test))' rlm_ldap: ldap_get_conn: Checking Id: 0 rlm_ldap: ldap_get_conn: Checking Id: 1 rlm_ldap: ldap_get_conn: Got Id: 1 rlm_ldap: attempting LDAP reconnection rlm_ldap: (re)connect to auth-01.mydomain.it:389, authentication 0 rlm_ldap: could not set LDAP_OPT_X_TLS_REQUIRE_CERT option to allow rlm_ldap: bind as cn=user,dc=mydomain,dc=it/passowrd to ldapserver.mydomain.it:389 rlm_ldap: waiting for bind result ... rlm_ldap: Bind was successful rlm_ldap: performing search in dc=mydomain,dc=it, with filter (&(gidNumber=801)(&(objectClass=posixGroup)(memberUid=test))) rlm_ldap::ldap_groupcmp: User found in group 801 rlm_ldap: ldap_release_conn: Release Id: 1 rlm_ldap: Pairs do not match. Rejecting user. rlm_ldap: ldap_release_conn: Release Id: 0 modcall[authorize]: module "ldap" returns reject for request 0 modcall: leaving group authorize (returns reject) for request 0 Delaying request 0 for 1 seconds Finished request 0 --------------------------- If you see in the bottom of the log, 'rlm_ldap::ldap_groupcmp: User found in group 801' but also 'rlm_ldap: Pairs do not match. Rejecting user' Any help really appreciated! Pietro
Pietro Accerboni wrote:
Hi, here is my problem: 0) Cisco APs - Radius - Ldap authentication via 802.1x - PEAP - MSCHAPv2 works.
That's a good start.
1) I need to link the group of the user that try to authenticate with the SSID, so i can allow only a particular group of users to use a particular SSID/VLAN.
i.e. IF the user is in SSID, AND he is NOT in a particular group, THEN reject the request.
7) I really connot figure out a correct configuration of: * ldap module in radius.conf
If PEAP works, your LDAP configuration is mostly OK.
* selection in users
See below.
* mapping of group attribute in ldap.attrmap
Don't.
(radius.conf, module ldap) ... compare_check_items = yes (if i do not set this, all users with valid credentials can log in!)
Set this to "No". The current configuration is preventing the *proper* users from logging in:
If you see in the bottom of the log, 'rlm_ldap::ldap_groupcmp: User found in group 801' but also 'rlm_ldap: Pairs do not match. Rejecting user'
See? Don't set it. It's not needed.
(users) DEFAULT Cisco-AVPair=="ssid=SISSA-STAFF", Ldap-Group==800 Fall-Through = no
This says "match SSID AND ldap group" ... and do nothing else. Compare that to what you wrote in (1) above. What you want is: DEFAULT Cisco-AVPair=="ssid=SISSA-STAFF", Ldap-Group!=800, Auth-Type := Reject (all on one line). See "man users" for a description of the operators. Alan DeKok.
Thanks a lot for the quick answer, it works! So the ldap filters i wrote are ok, the problem was on the users file. I have 2 more questions: 1) Now i check the group membership with a numeric constant, like Ldap-Group!=800. Say the ldap posixGroup entry is: cn=staff,dc=mydomain,dc=it cn=staff gidNumber=<gid> ... I want to pick out the gid from the group 'staff', whatever this numer is, and check this number in the users file. May I write something like gid=%{ldap:ldap://dc=mydomain,dc=it?gidNumber?sub?(&(posixGroup)(cn=staff))}, and then use this var in the test Ldap-Group!=<gid> in users file? 2) Maybe a stupid question. I found very difficult to have a clear understanding of how to configure freeradius, from the documentation that comes with the rpm/deb package and the one i found on freeradius.org. Also i look for a book, but the only one i found is 'Radius' from O'Reilly, that is old and far far far away from a 'good book'. Is there some paper, some book, some doc that explain clearly the freeradius world? From a general point of view (Radius Protocol, Difference in Authorization and Authentication section, etc..) to the details (how freeradius use the request attrs/config attrs/reply attrs, the gory details of the single module configuration switch - see my mistake with 'compare_check_items=yes' in ldap, etc.)? Thanks Pietro Alan DeKok wrote:
Pietro Accerboni wrote:
Hi, here is my problem: 0) Cisco APs - Radius - Ldap authentication via 802.1x - PEAP - MSCHAPv2 works.
That's a good start.
1) I need to link the group of the user that try to authenticate with the SSID, so i can allow only a particular group of users to use a particular SSID/VLAN.
i.e. IF the user is in SSID, AND he is NOT in a particular group, THEN reject the request.
7) I really connot figure out a correct configuration of: * ldap module in radius.conf
If PEAP works, your LDAP configuration is mostly OK.
* selection in users
See below.
* mapping of group attribute in ldap.attrmap
Don't.
(radius.conf, module ldap)
...
compare_check_items = yes (if i do not set this, all users with valid credentials can log in!)
Set this to "No". The current configuration is preventing the *proper* users from logging in:
If you see in the bottom of the log, 'rlm_ldap::ldap_groupcmp: User found in group 801' but also 'rlm_ldap: Pairs do not match. Rejecting
user'
See? Don't set it. It's not needed.
(users) DEFAULT Cisco-AVPair=="ssid=SISSA-STAFF", Ldap-Group==800 Fall-Through = no
This says "match SSID AND ldap group" ... and do nothing else. Compare that to what you wrote in (1) above.
What you want is:
DEFAULT Cisco-AVPair=="ssid=SISSA-STAFF", Ldap-Group!=800, Auth-Type := Reject
(all on one line). See "man users" for a description of the operators.
Alan DeKok. - List info/subscribe/unsubscribe? See http://www.freeradius.org/list/users.html
Pietro Accerboni wrote:
Thanks a lot for the quick answer, it works!
Yes. It's really that easy. The hard part is usually figuring out how to phrase the policies correctly. If the policies are phrased incorrectly, it's *impossible* to get the server to do what you want... because the policies aren't doing what you want.
So the ldap filters i wrote are ok, the problem was on the users file. I have 2 more questions: ... I want to pick out the gid from the group 'staff', whatever this numer is, and check this number in the users file. May I write something like gid=%{ldap:ldap://dc=mydomain,dc=it?gidNumber?sub?(&(posixGroup)(cn=staff))}, and then use this var in the test Ldap-Group!=<gid> in users file?
Unfortunately, no. This should be easier in 2.0.
2) Maybe a stupid question. I found very difficult to have a clear understanding of how to configure freeradius, from the documentation that comes with the rpm/deb package and the one i found on freeradius.org. Also i look for a book, but the only one i found is 'Radius' from O'Reilly, that is old and far far far away from a 'good book'.
Well, yes.
Is there some paper, some book, some doc that explain clearly the freeradius world? From a general point of view (Radius Protocol,
I've got a bit over 200 pages done on my book, but other issues keep coming up, and preventing me from doing much more.
Difference in Authorization and Authentication section, etc..) to the details (how freeradius use the request attrs/config attrs/reply attrs, the gory details of the single module configuration switch - see my mistake with 'compare_check_items=yes' in ldap, etc.)?
Generally, any module configuration is the least of your worries. The most effort is spent writing the correct policies. Alan DeKok.
participants (2)
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Alan DeKok -
Pietro Accerboni