2010/6/18 Stefan Sayer <stefan.sayer(a)googlemail.com>om>: Yes, there is no special reason for it. RFC 3261 - 25.1 ------------------------- Many SIP header field values consist of words separated by LWS or special characters. Unless otherwise stated, tokens are case- insensitive. ------------------------- As all we know the schema in a SIP/SIPS URI is case insensitive ("sip:" == "SIP:"): SIP-URI = "sip:" [ userinfo ] hostport uri-parameters [ headers ] However SIP methods are case sensitive ("INVITE" != "invite"): INVITEm = %x49.4E.56.49.54.45 ; INVITE in caps So *any* string appearing in SIP BNF (as "Digest", "MD5", "tag"....) are case insensitive. PS: /Ragel-SIP-Parser/sip_parser.sh Authorization 'Authorization: DIGEST username="Alice", realm="atlanta.com", nonce="84a4cc6f3082121f32b42a2187831a9e", response="7587245234b3434cc3412213e5f113a5"' OK ;) -- Iñaki Baz Castillo <ibc(a)aliax.net>