Sip Authentication Example - 3Com VCX V7122 User Manual

SIP Authentication Example

VCX V7122 gateway supports basic and digest authentication types, according to SIP RFC
3261 standard. A proxy server might require authentication before forwarding an INVITE
message. A Registrar/Proxy server may also require authentication for client registration. A
proxy replies to an unauthenticated INVITE with a 407 Proxy Authorization Required
response, containing a Proxy-Authenticate header with the form of the challenge. After
sending an ACK for the 407, the User Agent can then resend the INVITE with a Proxy-
Authorization header containing the credentials.
User Agent, Redirect or Registrar servers typically use 401 Unauthorized responses to
challenge authentication containing a WWW-Authenticate header, and expect the re-INVITE
to contain an Authorization header.
The following example describes the Digest Authentication procedure including computation
of User Agent credentials.
The REGISTER request is sent to Registrar/Proxy server for registration, as follows:
REGISTER sip:10.2.2.222 SIP/2.0
Via: SIP/2.0/UDP 10.1.1.200
From: <sip: 122@10.1.1.200>;tag=1c17940
To: <sip: 122@10.1.1.200>
Call-ID: 634293194@10.1.1.200
User-Agent: Audiocodes-Sip-Gateway/TrunkPack 1610/v.4.20.299.412
CSeq: 1 REGISTER
Contact: sip:122@10.1.1.200:
Expires:3600
On receiving this request the Registrar/Proxy returns 401 Unauthorized response.
SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 10.2.1.200
From: <sip:122@10.2.2.222 >;tag=1c17940
To: <sip:122@10.2.2.222 >
Call-ID: 634293194@10.1.1.200
Cseq: 1 REGISTER
Date: Mon, 30 Jul 2001 15:33:54 GMT
Server: Columbia-SIP-Server/1.17
Content-Length: 0
WWW-Authenticate: Digest realm="audiocodes.com",
nonce="11432d6bce58ddf02e3b5e1c77c010d2",
stale=FALSE,
algorithm=MD5
According to the sub-header present in the WWW-Authenticate header the correct
REGISTER request is formed.
Since the algorithm used is MD5, take:
The username from the ini file: VCX V7122 -3Com
The realm return by the proxy: 3Com.com
The password from the ini file: 3Com.
The equation to be evaluated: (according to RFC this part is called A1).
160 3Com VCX V7122 SIP VoIP Gateway User Manual