I am pretty newbie to Linux, as most of computers for resources in my school use Linux, I just installed Ubuntu to learn.
ufw sets policy as under:
IPTABLES -P INPUT DROP IPTABLES -P FORWARD DROP IPTABLES -P OUTPUT ACCEPT
ufw default deny (default incoming).
In both cases, Linux all distros trust all applications including fames ftp, smtp, SSH, mail and all others allowing for outgoing traffic without notice or without concent. Which in turn leaves all 0-to-65535 ports open for outgoing traffic for all installed applications.
Furthermore, there is no particular application control that which particular application like firefox, opera or other are granted access to internet in any firewalls so far I tried. All installed application can freely enjoys all freedom to access internet.
In all major distros
netstat is tempered to provide minimum information.
My concern is security.... How much security is offered by the OS (Linux), which allows all outgoing traffic and just blocks the access to incoming?