I am trying to authenticate using a link-local IPv6 address. I was reading http://lists.freeradius.org/pipermail/freeradius-users/2013-May/066690.html, but I assume it is old already? $ radtest -6 user password 'fe80::link-local-ipv6-address%eth0' 0 'secret' 0 'fe80::link-local-ipv6-address' # <--------- radtest --version = 2.2.8 Sending Access-Request of id 68 to 'fe80::link-local-ipv6-address' port 1812 User-Name = "user" User-Password = "password" NAS-IPv6-Address = 'fe80::link-local-ipv6-address' NAS-Port = 0 Message-Authenticator = 0x00000000000000000000000000000000 ^C $ ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── # Example of passing request (1) Sent Access-Accept Id 74 from [global-ipv6-address]:1812 to [global-ipv6-address]:52427 length 0 (1) Reply-Message = "Hello, user" (1) Finished request Waking up in 4.9 seconds. (1) Cleaning up request packet ID 74 with timestamp +42 Ready to process requests Ignoring request to auth address :: port 1812 bound to server default from unknown client 'fe80::link-local-ipv6-address' port 45077 proto udp Ready to process requests I already have the clients setup correctly and they work: client LinkLocal { ipv6addr = fd80::/16 secret = "secret" require_message_authenticator = yes nastype = other } client Global { ipv6addr = fd00::/16 secret = "secret" require_message_authenticator = yes nastype = other } I would prefer a solution of 2.2.8 FreeRadius, but I could consider updating. Ντέντος Σταύρος