Hi, 

1.) Here INVITE message sent to IPv6 SIP Client, but he doesnt respond: 

INVITE sip:jano@[2001:4118:300:122:bca7:31ac:ccab:d6f6];line=e7b07b8cb7a33ee SIP/2.0

Record-Route: <sip:[2001:4118:300:122:444A:3FFF:FECC:61A0];lr=on>

Record-Route: <sip:[2001:4118:300:122:A00:27FF:FE60:83C];r2=on;lr=on;nat=v46>

Record-Route: <sip:158.193.139.207;r2=on;lr=on;nat=v46>

Record-Route: <sip:158.193.139.46;lr=on;nat=yes>

Via: SIP/2.0/UDP [2001:4118:300:122:444A:3FFF:FECC:61A0];branch=z9hG4bK1c7c.bf9123f4.0

Via: SIP/2.0/UDP [2001:4118:300:122:A00:27FF:FE60:83C];branch=z9hG4bK1c7c.76b1542.0

Via: SIP/2.0/UDP 158.193.139.46;rport=5060;branch=z9hG4bK1c7c.af9123f4.0

Via: SIP/2.0/UDP 10.0.2.15:5060;received=158.193.139.205;rport=55754;branch=z9hG4bK1417756364

From: <sip:jakub@ip02.sip.uniza.sk>;tag=632445346

To: <sip:jano@ip02.sip.uniza.sk>

Call-ID: 267806174

CSeq: 21 INVITE

Contact: <sip:jakub@158.193.139.205:55754>

Content-Type: application/sdp

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO

Max-Forwards: 67

User-Agent: Linphone/3.3.2 (eXosip2/3.3.0)

Subject: Phone call

Content-Length:   470

P-hint: outbound

v=0

o=jakub 123456 654321 IN IP6 2001:4118:300:122:a00:27ff:fe60:83c

s=A conversation

c=IN IP6 2001:4118:300:122:a00:27ff:fe60:83c

t=0 0

m=audio 51652 RTP/AVP 112 111 110 3 0 8 101

a=rtpmap:112 speex/32000/1

a=fmtp:112 vbr=on

a=rtpmap:111 speex/16000/1

a=fmtp:111 vbr=on

a=rtpmap:110 speex/8000/1

a=fmtp:110 vbr=on

a=rtpmap:3 GSM/8000/1

a=rtpmap:0 PCMU/8000/1

a=rtpmap:8 PCMA/8000/1

a=rtpmap:101 telephone-event/8000/1

a=fmtp:101 0-11

a=nortpproxy:yes

2.) I get here cap files of SIPv64 server and Bridge as Enclosure.

Here i get my hosts file for wireshark for clear view of SIP entities:

158.193.139.46 SIPserver_IP4

158.193.139.207 Bridge_IP4

2001:4118:300:122:444a:3fff:fecc:61a0 SIPserver_IP6

2001:4118:300:122:a00:27ff:fe60:83c Bridge_IP6

158.193.139.205 WinPC_IP4

2001:4118:300:122:bca7:31ac:ccab:d6f6 IP6_Client

10.0.2.15 IP4_Klient