pb fingerprint icmp on netfilter/linux

[rmkml]

Hi,
I have a little pb, Im received icmp ping echo request,
normaly echo request are type 8 and code 0,
but this echo request are type 8 and code 19 !
my iptables rules is :
  iptables -A INPUT -j ACCEPT -p icmp --icmp-type echo-request

maybe add check code on netfilter ?

another question, but this is not good list, but send my question,
why linux kernel 2.6.7 (my test), accept and reply type 0 code 19 ?
(code 19 is unknown)

Regards
Rmkml