RADIUS Extension for Digest Authentication
RFC 4590

Page 26
      NAS-IP-Address = a 0 45 26 (10.0.69.38)
Probably IP address should be changed to be in accordance with
IP addresses for examples (RFC3330), i.e. 192.0.2.0/24 range

The authors might note, contrary to impllication of the motivational text in 1.2, that RFC3261 did not intend to supplant Digest authentication with TLS and S/MIME. Digest is still mandatory and is the preferred way for a UA to authenticate itself to a proxy server. This just furthers the need for this mechanism, of course - the text in 1.2 makes it sound like Digest a legacy mechanism for SIP.

  Please include an informative reference for CHAP in section 1.3.

  Section 3.1 says:
  >
  > The RADIUS server MAY have added a Digest-Nextnonce attribute into an
  > Access-Accept packet.  If the RADIUS client discovers this, it puts
  > the contents of this attribute into a 'nextnonce' directive.  Now it
  > can send an HTTP-style response.
  >
  Perhaps a better wording might be:
  >
  > When the RADIUS server provides a Digest-Nextnonce attribute in the
  > Access-Accept packet, the RADIUS client puts the contexts of this
  > attribute into a 'nextnonce' directive so that it can send an
  > HTTP-style response.

  Section 4.9 says:
  >
  >4.9.  Digest-Algorithm attribute
  >
  >   Type
  >
  s/Type/Description/

  Section 4.20 says:
  >
  >4.20.  SIP-AOR
  >
  >   Type
  >
  s/Type/Description/

  Section 7 says:
  >
  > A->B
  >
  >    INVITE sip:97226491335@example.com SIP/2.0
  >    Proxy-Authorization: Digest algorithm="md5",nonce="3bada1a0"
  >         ,opaque="",realm="example.com"
  >         ,response="f3ce87e6984557cd0fecc26f3c5e97a4"
  >         ,uri="sip:97226491335@10.0.69.38",username="12345678"
  >    From: <sip:12345678@example.com>
  >    To: <sip:97226491335@example.com>
  >
  > B->C
  >
  >    Code = 1 (Access-Request)
  >    Attributes:
  >    NAS-IP-Address = a 0 45 26 (10.0.69.38)
  >    NAS-Port-Type = 5 (Virtual)
  >    User-Name = "12345678"
  >    Digest-Response = "f3ce87e6984557cd0fecc26f3c5e97a4"
  >    Digest-Realm = "example.com"
  >    Digest-Nonce = "3bada1a0"
  >    Digest-Method = "INVITE"
  >    Digest-URI = "sip:97226491335@example.com"
  >
  Why is the value of Digest-URI not the same URI provided by A?