RADIUS attribute from rfc5090
This attribute describes a protection space component of the
RADIUS server. HTTP-style protocols differ in their definition
of the protection space. See, for
details. It MUST only be used in Access-Request, Access-
Challenge, and Accounting-Request packets.
104 for Digest-Realm
In Access-Requests, the RADIUS client takes the value of the
realm directive (realm-value according to ) without
surrounding quotes from the HTTP-style request it wants to
authenticate. In Access-Challenge packets, the RADIUS server
puts the expected realm value into this attribute.