Thank you for your help, i never heard about it, i was usually using ping and traceroute command. i am not a specialist. I maybe gave a wrong explanation, but as you said it's not about pfsense son i should ask to ubuntu users. My question was about why it was working when the dhcp on pfsense was enabled and static ip on ubuntu, but not with dhcp was disabled and static ip on ubuntu. For sure it's something about the dns I hoped to find an answer here because i thought i has something to do with the dhcp server but it's not...
I'll try other linux/ubuntu forums or just switch to another operating system.
Many thanks for your help man ! I appreciate it, you made me understand things I understood/learned wrong.
Big up ;-)