o.k. the man page isn't very helpful I want to pass a value for NAS-IP-Address to eapol_test as an argument. the man page says -N attr spec Send arbitrary attribute specific by attr_id:syntax:value, or attr_id alone. attr_id should be the numeric ID of the attribute, and syntax should be one of 's' (string), 'd' (integer), or 'x' (octet string). The value is the attribute value to send. When attr_id is given alone, NULL is used as the attribute value. Multiple attributes can be specified by using the option several times. so I wanted to pass 144.32.126.139 as the NAS-IP-Address I've tried eapol_test -c /usr/local/etc/peap-ydh.conf -A 144.32.126.139 -a 144.32.128.68 -s <key> -N 61:d:15 -N 6:d:8 -N 4:s:144.32.126.139 but that gives me Attribute 4 (NAS-IP-Address) length=16 Invalid IP address length 14 Putting the address in quotes makes no difference other even tried -N 4:x:061064064056063062056061062066054061063071 which should be 144.32.126.139 in octal Still got an invalid IP address Length Any Ideas? A