Hi I’m using FreeRadius 2.1.12 wih mschap and ntlm_auth external execution module as follows: ntlm_auth = "/usr/bin/ntlm_auth --request-nt-key --username=%{%{Stripped-User-Name}:-%{%{User-Name}:-None}} --challenge=%{%{mschap:Challenge}:-00} --nt-response=%{%{mschap:NT-Response}:-00}" I want to run ntlm_auth from command line so enabled auth_log to get challenge and response: MS-CHAP-Challenge = 0x8f89ccd88332fd05b75cd39a9d08c296 MS-CHAP2-Response = 0x0100a6a4eb77926c3f1e7f78254b08f720a800000000000000002a0c1f094749304c3d11cdc8376cbe4373de0d61c2823011 I’m running ntlm_auth from command line with those parameters: /usr/bin/ntlm_auth --request-nt-key –username=kimia-mo --challenge=8f89ccd88332fd05b75cd39a9d08c296 --nt-response=0100a6a4eb77926c3f1e7f78254b08f720a800000000000000002a0c1f094749304c3d11cdc8376cbe4373de0d61c2823011 And Got error: hex decode of 8f89ccd88332fd05b75cd39a9d08c296 failed! (only got 16 bytes) with radius –X , I saw that the challenge and response is differ from that I got in auth_log in same session. So if I run ntlm_auth with new values, it’s OK! what’s wrong?