INVITE sip:vivekg@chair.dnrc.bell-labs.com SIP/2.0 TO : sip:vivekg@chair.dnrc.bell-labs.com ; tag = 1a1b1f1H33n From : "J Rosenberg \\\"" ; tag = 98asjd8 CaLl-Id : 0ha0isndaksdj@10.1.1.1 cseq: 8 INVITE Via : SIP / 2.0 /UDP 135.180.130.133 Subject : NewFangledHeader: newfangled value more newfangled value Content-Type: application/sdp v: SIP / 2.0 / TCP 12.3.4.5 ; branch = 9ikj8 , SIP / 2.0 / UDP 1.2.3.4 ; hidden m:"Quoted string \"\"" ; newparam = newvalue ; secondparam = secondvalue ; q = 0.33 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 s= c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This message tests support for Proxy-Require and Require INVITE sip:user@company.com SIP/2.0 To: sip:j_user@company.com From: sip:caller@university.edu Call-ID: 0ha0isndaksdj@10.1.1.1 Require: newfeature1, newfeature2 Proxy-Require: newfeature3, newfeature4 CSeq: 8 INVITE Via: SIP/2.0/UDP 135.180.130.133 |This message contains unknown schemes in the Request URI, To, From and Contact headers. INVITE name:John_Smith SIP/2.0 To: isbn:2983792873 From: http://www.cs.columbia.edu Call-ID: 0ha0isndaksdj@10.1.2.3 CSeq: 8 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Contact: Joe Bob Briggs v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This message is a registration request with an expiration year of 2040 REGISTER sip:company.com SIP/2.0 To: sip:user@company.com From: sip:user@company.com Contact: sip:user@host.company.com Call-ID: 0ha0isndaksdj@10.0.0.1 CSeq: 8 REGISTER Via: SIP/2.0/UDP 135.180.130.133 Expires: Thu, 01 Dec 2040 16:00:00 GMT |It is a request that includes an Accept header without SDP. INVITE sip:user@company.com SIP/2.0 To: sip:j_user@company.com From: sip:caller@university.edu Call-ID: 0ha0isndaksdj@10.0.0.1 Accept: text/newformat CSeq: 8 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: 148 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 | INVITE sip:user@comapny.com SIP/2.0 To: sip:j.user@company.com From: sip:caller@university.edu Call-ID: 0ha0isndaksdj@10.0.0.1 CSeq: 8 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/newformat Content-Length: 42 |This request message contains a new method, NEWMETHOD NEWMETHOD sip:user@comapny.com SIP/2.0 To: sip:j.user@company.com From: sip:caller@university.edu Call-ID: 0ha0isndaksdj@10.0.0.1 CSeq: 8 NEWMETHOD Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: 148 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This message is nearly identical to test7. but cseq does not match! NEWMETHOD sip:user@comapny.com SIP/2.0 To: sip:j.user@company.com From: sip:caller@university.edu Call-ID: 0ha0isndaksdj@10.0.1.1 CSeq: 8 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: 148 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This message is a REGISTER request with an unknown authorization scheme REGISTER sip:company.com SIP/2.0 To: sip:j.user@company.com From: sip:j.user@company.com Call-ID: 0ha0isndaksdj@10.0.1.1 CSeq: 8 REGISTER Via: SIP/2.0/UDP 135.180.130.133 Authorization: Super-PGP ajsohdaosdh0asyhdaind08yasdknasd09asidhas0d8 |Content-length is wrong (and Multiple SIP requests per UDP packet are no longer allowed.) REGISTER sip:company.com SIP/2.0 To: sip:j.user@company.com From: sip:j.user@company.com Call-ID: 0ha0isndaksdj@10.0.2.2 Contact: sip:j.user@host.company.com CSeq: 8 REGISTER Via: SIP/2.0/UDP 135.180.130.133 Content-Length: 0 INVITE sip:joe@company.com SIP/3.0 To: sip:joe@company.com From: sip:caller@university.edu Call-ID: 0ha0isnda977644900765@10.0.0.1 CSeq: 8 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |The message contains a request with an extra Call-ID and To field INVITE sip:user@company.com SIP/2.0 CSeq: 0 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 | extra callid: should respond with an error! INVITE sip:user@company.com SIP/2.0 Via: SIP/2.0/UDP 135.180.130.133 CSeq: 0 INVITE Call-ID: 98asdh@10.1.1.1 Call-ID: 98asdh@10.1.1.2 From: sip:caller@university.edu From: sip:caller@organization.org To: sip:user@company.com Content-Type: application/sdp v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This message contains an Expires header which has illegal values INVITE sip:user@company.com SIP/2.0 Via: SIP/2.0/UDP 135.180.130.133 CSeq: 0 INVITE Call-ID: 98asdh@10.1.1.2 Expires: Thu, 44 Dec 19999 16:00:00 EDT From: sip:caller@university.edu To: sip:user@company.com Content-Type: application/sdp v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This message is a response with a 2nd Via header of 255.255.255.255 SIP/2.0 200 OK Via: SIP/2.0/UDP 135.180.130.57;branch=0 Via: SIP/2.0/UDP 255.255.255.255;branch=0 Call-ID: 0384840201@10.1.1.1 CSeq: 0 INVITE From: sip:user@company.com To: sip:user@university.edu;tag=2229 Content-Type: application/sdp v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 224.2.17.12/127 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This is a request with the Via and Contact headers incorrect INVITE sip:user@company.com SIP/2.0 To: sip:j.user@company.com From: sip:caller@university.edu Call-ID: 0ha0isndaksdj@10.0.0.1 CSeq: 8 INVITE Via: SIP/2.0/UDP 135.180.130.133;;,; Contact: "" <> ;,"Joe" ;;,,;; Content-Type: application/sdp v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This is a request message with a Content Length that is much larger than the length of the body INVITE sip:user@company.com SIP/2.0 To: sip:j.user@company.com From: sip:caller@university.edu Call-ID: 0ha0isndaksdj@10.0.0.1 CSeq: 8 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: 9999 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This is a request message with a negative value for Content-Length INVITE sip:user@company.com SIP/2.0 To: sip:j.user@company.com From: sip:caller@university.edu Call-ID: 0ha0isndaksdj@10.0.0.1 CSeq: 8 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: -999 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This is a request message with garbage after the end of the SDP included in the body. INVITE sip:user@company.com SIP/2.0 To: sip:j.user@company.com From: sip:caller@university.edu Call-ID: 0ha0isndaksdj@10.0.0.1 CSeq: 8 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: 148 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 asdpasd08asdsdk:;;asd a0sdjhg8a0''...'';;;; |This is a request with an unterminated quote in the display name of the To field INVITE sip:user@company.com SIP/2.0 To: "Mr. J. User From: sip:caller@university.edu Call-ID: 0ha0isndaksdj@10.0.0.1 CSeq: 8 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: 138 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This is an INVITE request with a semicolon-separated parameter in the "user" part INVITE sip:user;par=u%40h.com@company.com SIP/2.0 To: sip:j_user@company.com From: sip:caller@university.edu Call-ID: 0ha0isndaksdj@10.1.1.1 CSeq: 8 INVITE Via: SIP/2.0/UDP 135.180.130.133 |This INVITE is illegal because the Request-URI has been enclosed within in "<>" INVITE SIP/2.0 To: sip:user@company.com From: sip:caller@university.edu Call-ID: 1@10.0.0.1 CSeq: 1 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: 178 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 s=SIP Call t=3149328700 0 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This INVITE has illegal LWS within the SIP URL. INVITE sip:user@company.com; transport=udp SIP/2.0 To: sip:user@company.com From: sip:caller@university.edu Call-ID: 2@10.0.0.1 CSeq: 1 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: 178 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 s=SIP Call t=3149328700 0 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This INVITE has illegal >1 SP between elements of the Request-URI. INVITE sip:user@company.com SIP/2.0 To: sip:user@company.com From: sip:caller@university.edu Call-ID: 3@10.0.0.1 CSeq: 1 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: 178 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 s=SIP Call c=IN IP4 135.180.130.88 t=3149328700 0 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This INVITE is legal and has a Request-URI with a SIP URL containing escaped characters INVITE sip:sip%3Auser%40example.com@company.com;other-param=summit SIP/2.0 To: sip:user@company.com From: sip:caller@university.edu Call-ID: 4@10.0.0.1 CSeq: 1 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: 178 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 s=SIP Call c=IN IP4 135.180.130.88 t=3149328700 0 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This INVITE is illegal as it the Request-URI contains a SIP URL containing escaped headers INVITE sip:user@company.com?Route=%3Csip:sip.example.com%3E SIP/2.0 To: sip:user@company.com From: sip:caller@university.edu Call-ID: 5@10.0.0.1 CSeq: 1 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: 178 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 s=SIP Call c=IN IP4 135.180.130.88 t=3149328700 0 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This INVITE contains an unknown URI scheme in the Request-URI. INVITE name:user SIP/2.0 To: sip:user@company.com From: sip:caller@university.edu Call-ID: 6@10.0.0.1 CSeq: 1 INVITE Via: SIP/2.0/UDP 135.180.130.133 Content-Type: application/sdp Content-Length: 178 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 s=SIP Call c=IN IP4 135.180.130.88 t=3149328700 0 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This OPTIONS request is legal despite there being no LWS between the display name and < in the From header. OPTIONS sip:user@company.com SIP/2.0 To: sip:user@company.com From: "caller" Call-ID: 1234abcd@10.0.0.1 CSeq: 1 OPTIONS Via: SIP/2.0/UDP 135.180.130.133 |This OPTIONS request is legal despite there being extra LWS between the display name and < in the From header. OPTIONS sip:user@company.com SIP/2.0 To: sip:user@company.com From: "caller" Call-ID: 1234abcd@10.0.0.1 CSeq: 2 OPTIONS Via: SIP/2.0/UDP 135.180.130.133 |This INVITE is illegal as it contains a non GMT time zone in the SIP Date of the Expires header. INVITE sip:user@company.com SIP/2.0 To: sip:user@company.com From: sip:caller@university.edu Call-ID: 7@10.0.0.1 CSeq: 1 INVITE Via: SIP/2.0/UDP 135.180.130.133 Expires: Fri, 01 Jan 2010 16:00:00 EST Content-Type: application/sdp Content-Length: 178 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 s=SIP Call t=3149328700 0 c=IN IP4 135.180.130.88 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This is a legal INVITE but the message content has long since expired. INVITE sip:user@company.com SIP/2.0 To: sip:user@company.com From: sip:caller@university.edu Call-ID: 8@10.0.0.1 CSeq: 1 INVITE Via: SIP/2.0/UDP 135.180.130.133 Expires: Thu, 01 Dec 1994 16:00:00 GMT Content-Type: application/sdp Content-Length: 178 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 s=SIP Call c=IN IP4 135.180.130.88 t=3149328700 0 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This is a legal SIP request with the Max-Forwards header set to zero. INVITE sip:user@company.com SIP/2.0 To: sip:user@company.com From: sip:caller@university.edu Call-ID: 9@10.0.0.1 CSeq: 1 INVITE Via: SIP/2.0/UDP 135.180.130.133 Max-Forwards: 0 Content-Type: application/sdp Content-Length: 178 v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 s=SIP Call c=IN IP4 135.180.130.88 t=3149328700 0 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This is a legal REGISTER message where the Contact header contains a SIP URL with an escaped header within it. REGISTER sip:company.com SIP/2.0 To: sip:user@company.com From: sip:user@company.com Contact: sip:user@host.company.com Call-ID: k345asrl3fdbv@10.0.0.1 CSeq: 1 REGISTER Via: SIP/2.0/UDP 135.180.130.133 Contact: |This is an illegal message as the REGISTER request contains a SIP URL with an escaped header but it is not enclosed in <> REGISTER sip:company.com SIP/2.0 To: sip:user@company.com From: sip:user@company.com Contact: sip:user@host.company.com Call-ID: k345asrl3fdbv@10.0.0.1 CSeq: 1 REGISTER Via: SIP/2.0/UDP 135.180.130.133 Contact: sip:user@example.com?Route=%3Csip:sip.example.com%3E |This is a legal message that contains long values in many headers. INVITE sip:user@company.com SIP/2.0 To: "I have a user name of extreme proportion" From: sip:caller@university.edu Call-ID: kl24ahsd546folnyt2vbak9sad98u23naodiunzds09a3bqw0sdfbsk34poouymnae0043nsed09mfkvc74bd0cuwnms05dknw87hjpobd76f CSeq: 1 INVITE My-State: sldkjflzdsfaret0803adgaasd0afds0asdaasd Via: SIP/2.0/UDP sip33.example.com Via: SIP/2.0/UDP sip32.example.com Via: SIP/2.0/UDP sip31.example.com Via: SIP/2.0/UDP sip30.example.com Via: SIP/2.0/UDP sip29.example.com Via: SIP/2.0/UDP sip28.example.com Via: SIP/2.0/UDP sip27.example.com Via: SIP/2.0/UDP sip26.example.com Via: SIP/2.0/UDP sip25.example.com Via: SIP/2.0/UDP sip24.example.com Via: SIP/2.0/UDP sip23.example.com Via: SIP/2.0/UDP sip22.example.com Via: SIP/2.0/UDP sip21.example.com Via: SIP/2.0/UDP sip20.example.com Via: SIP/2.0/UDP sip19.example.com Via: SIP/2.0/UDP sip18.example.com Via: SIP/2.0/UDP sip17.example.com Via: SIP/2.0/UDP sip16.example.com Via: SIP/2.0/UDP sip15.example.com Via: SIP/2.0/UDP sip14.example.com Via: SIP/2.0/UDP sip13.example.com Via: SIP/2.0/UDP sip12.example.com Via: SIP/2.0/UDP sip11.example.com Via: SIP/2.0/UDP sip10.example.com Via: SIP/2.0/UDP sip9.example.com Via: SIP/2.0/UDP sip8.example.com Via: SIP/2.0/UDP sip7.example.com Via: SIP/2.0/UDP sip6.example.com Via: SIP/2.0/UDP sip5.example.com Via: SIP/2.0/UDP sip4.example.com Via: SIP/2.0/UDP sip3.example.com Via: SIP/2.0/UDP sip2.example.com Via: SIP/2.0/UDP sip1.example.com Via: SIP/2.0/UDP host.example.com;received=135.180.130.133;branch=C1C3344E2710000000E299E568E7potato10potato0potato0 Content-Type: application/sdp v=0 o=mhandley 29739 7272939 IN IP4 126.5.4.3 s=SIP Call c=IN IP4 135.180.130.88 t=3149328700 0 m=audio 49210 RTP/AVP 0 12 m=video 3227 RTP/AVP 31 a=rtpmap:31 LPC/8000 |This is an illegal and badly mangled message. OPTIONS sip:135.180.130.133 SIP/2.0 Via: SIP/2.0/UDP company.com:5604 From: sip:iuser@company.com To: sip:user@135.180.130.133 Call-ID: 1804928587@company.com CSeq: 1 OPTIONS Expires: 0 0l@company.com To: sip:user@135.180.130.133 Call-ID: 1804928587@company.com CSeq: 1 OPTIONS Contact: sip:host.company.com Expires: 0xpires: 0sip:host.company.com Expires: 0 Contact: sip:host.company.com |This is a legal message with a large number of SDP attributes and a long telephone subscriber Request-URI INVITE sip:+1-972-555-2222;phone-context=name%40domain;new=user?%22Route%3a%20X%40Y%3bZ=W%22@gw1.wcom.com;user=phone SIP/2.0 Via: SIP/2.0/UDP iftgw.there.com:5060 From: sip:+1-303-555-1111@ift.here.com;user=phone To: sip:+1-650-555-2222@ss1.wcom.com;user=phone Call-ID: 1717@ift.here.com CSeq: 56 INVITE Content-Type: application/sdp Content-Length: 350 v=0 o=faxgw1 2890844527 2890844527 IN IP4 iftgw.there.com s=Session SDP c=IN IP4 iftmg.there.com t=0 0 m=image 49172 udptl t38 a=T38FaxVersion:0 a=T38maxBitRate:14400 a=T38FaxFillBitRemoval:0 a=T38FaxTranscodingMMR:0 a=T38FaxTranscodingJBIG:0 a=T38FaxRateManagement:transferredTCF a=T38FaxMaxBuffer:260 a=T38FaxUdpEC:t38UDPRedundancy |This REGISTER contains a contact where the 'user' parameter should be interpreted as being a contact-param and not a url-param. The register should succeed but a subsequent retrieval of the registration must not include "user=phone" as a url-parameter. REGISTER sip:bell-tel.com SIP/2.0 Via: SIP/2.0/UDP saturn.bell-tel.com From: sip:watson@bell-tel.com To: sip:watson@bell-tel.com Call-ID: 70710@saturn.bell-tel.com CSeq: 2 REGISTER Contact: sip:+1-972-555-2222@gw1.wcom.com;user=phone |This register contains a contact where the 'user' parameter is a url-param. The register should succeed and a subsequent retrieval of the registration must include "user=phone" as a url-parameter. REGISTER sip:bell-tel.com SIP/2.0 Via: SIP/2.0/UDP saturn.bell-tel.com From: sip:watson@bell-tel.com To: sip:watson@bell-tel.com Call-ID: 70710@saturn.bell-tel.com CSeq: 3 REGISTER Contact: |This is a legal INVITE where the To and From header contain display names that contain multiple tokens but are unquoted INVITE sip:t.watson@ieee.org SIP/2.0 Via: SIP/2.0/UDP c.bell-tel.com From: A. Bell To: T. Watson Call-ID: 31414@c.bell-tel.com CSeq: 1 INVITE |This is an illegal invite at the display names in the To and From headers contain non-token characters but are unquoted. A server may be intelligent enough to cope with this but may also return a 400 response with an appropriate reason phrase. INVITE sip:t.watson@ieee.org SIP/2.0 Via: SIP/2.0/UDP c.bell-tel.com From: Bell, Alexander To: Watson, Thomas Call-ID: 31415@c.bell-tel.com CSeq: 1 INVITE |This should be rejected with 400. Section 4.1 lists SIP version as a literal and doesn't say anything about ignoring leading zeros. As an example of why rejecting it is a good idea, consider version numbers like 2.1 and 2.01 - they are unlikely to refer to the same version. INVITE sip:t.watson@ieee.org SIP/02.00 Via: SIP/2.0/UDP c.bell-tel.com From: A. Bell To: T. Watson Call-ID: 31416@c.bell-tel.com CSeq: 1 INVITE |This is an illegal INVITE as the SIP Protocol version is unknown. INVITE sip:t.watson@ieee.org SIP/7.0 Via: SIP/2.0/UDP c.bell-tel.com From: A. Bell To: T. Watson Call-ID: 31417@c.bell-tel.com CSeq: 1 INVITE |