[OpenSIPS-Users] Opensips and VirtualBox - register problem

[cbulist]

Hi,

I installed Opensips (1.5.1-notls) in VirtualBox running Centos.
The instalation process was without problem (with mysql module), I 
created the database and added a user to try it with a Xlite softphone 
but when I try to register the user I got:

SIP/2.0 401 Unauthorized

My scenario is:

IP of Centos running in virtualbox: 192.168.1.104
IP Softphone: 192.168.1.101


ngrep:

filter: (ip) and ( port 5060 )
#
U 192.168.1.101:6000 -> 192.168.1.104:5060
REGISTER sip:192.168.1.104 
SIP/2.0..Via:SIP/2.0/UDP192.168.56.1:6000;rport;branch=z9hG4bK32C8DAAEFF6F4D8D80E365714D3E3A3E..From: 
3000 <sip:3000 at 192.168.1.104>..To: 3000 
<sip:3000 at 192.168.1.104>..Contact: "3000" 
<sip:3000 at 192.168.56.1:6000>..Call-ID:398B09DE8F2F41F0ACCFBA2AFCAC1156 at 192.168.1.104..CSeq: 
48632 REGISTER..Expires: 1800..Max-Forwards: 70..User-Agent: X-PRO build 
1082..Content-Length: 0....
#

U 192.168.1.104:5060 -> 192.168.1.101:6000
   SIP/2.0 401 Unauthorized..Via: SIP/2.0/UDP 
192.168.56.1:6000;rport=6000;branch=z9hG4bK32C8DAAEFF6F4D8D80E365714D3E3A3E;received=192.168.1.101..From: 
3000 <sip:3000 at 192.168.1.104>..To: 3000 
<sip:3000 at 192.168.1.104>;tag=c97b4d1cb1f3d0da549e06a8d482ef63.98b8..Call-ID:398B09DE8F2F41F0ACCFBA2AFCAC1156 at 192.168.1.104..CSeq: 
48632 REGISTER..WWW-Authenticate: Digest 
realm="192.168.1.104",nonce="4a65a8af00001030e9b5d3f2548a48cc2e8f1387638d5db6"..Server: 
OpenSIPS (1.5.1-notls (i386/linux))..Content-Length: 0....

is a NAT problem?...Any idea?

Thanks in advance