Oh, there is a problem. No doubt to me. 99% it's related to some FreeBSD configuration I"ve done of my own or due to upgrading process of system or ports. For example it happens I lost the lo0 in the rc.conf. No idea why but I had network_interfaces="xl0" in my rc.conf instead of "xlo lo0".
I'm also 100% sure that if I can reinstall FreeBSD from scratch this problem should disapear but this is an hard work to do. I even could compare my config files before and after and find the problem too.
Anyway here is my rc.conf :
hostname=mururoa2.
ifconfig_xl0=dhcp
keymap="us.iso"
linux_enable="YES"
moused_enable="YES"
sshd_enable="YES"
cupsd_enable="YES"
network_interfaces="xl0 lo0"
About sysctl, no I've done any configuration there and my sysctl.conf is only # xxx.
Oups, declaring DNS servers from my provider solve the problem for good
That dont make me understand why I dont see any problem with windows and linux using same configuration (dhcp) on the same box ...