Pf does not seem to allow UDP packets destined for port 0 out, TCP packets to 
the same port pass without problems.
If nothing else, this breaks nmaps os-detection mode.

with 'pass quick on em0'
#>hping -2 -n -p 0 192.168.1.10
HPING 192.168.1.10 (em0 192.168.1.10): udp mode set, 28 headers + 0 data bytes
[send_ip] sendto: No route to host

with 'set skip on em0':
#> hping -2 -n -p 0 192.168.1.10
HPING 192.168.1.10 (em0 192.168.1.10): udp mode set, 28 headers + 0 data bytes
ICMP Port Unreachable from ip=192.168.1.10

Is this intentional and if so, why?

Reply via email to