Need help with iptables

[Markus]

Well, now I tried $ping localhost and it replied with all packets, so I did:
$echo 0 > /proc/sys/net/ipv4/ip_forward
$echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
$echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_all

.... which took care of the ping problem, but I don't get it; why did my computer answer.

This is $iptables -L

Chain INPUT (policy DROP)
target     prot opt source               destination
ACCEPT     all  --  anywhere             anywhere
ACCEPT     icmp --  anywhere             anywhere            state ESTABLISHED
ACCEPT     tcp  --  anywhere             anywhere            state ESTABLISHED
ACCEPT     udp  --  anywhere             anywhere            state ESTABLISHED
DROP       icmp --  anywhere             anywhere
ACCEPT     all  --  anywhere             anywhere            state RELATED,ESTABLISHED
ACCEPT     all  --  anywhere             anywhere            state RELATED,ESTABLISHED
DROP       tcp  --  anywhere             anywhere            tcp dpt:ftp-data
DROP       tcp  --  anywhere             anywhere            tcp dpt:ftp
REJECT     tcp  --  anywhere             anywhere            tcp dpt:ftp-data reject-with icmp-port-unreachable
REJECT     tcp  --  anywhere             anywhere            tcp dpt:ftp reject-with icmp-port-unreachable
ACCEPT     tcp  --  anywhere             anywhere            tcp dpts:6881:6883
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:6969
DROP       tcp  --  anywhere             anywhere            tcp spt:31337 dpt:31337
DROP       all  --  10.0.0.0/8           anywhere
DROP       all  --  127.0.0.0/8          anywhere
DROP       all  --  172.16.0.0/12        anywhere
DROP       all  --  192.168.0.0/16       anywhere
DROP       tcp  --  anywhere             anywhere            tcp spt:69
DROP       tcp  --  anywhere             anywhere            tcp spt:135
REJECT     tcp  --  anywhere             anywhere            tcp dpt:netbios-ssn reject-with icmp-port-unreachable
REJECT     tcp  --  anywhere             anywhere            tcp dpt:microsoft-ds reject-with icmp-port-unreachable
REJECT     tcp  --  anywhere             anywhere            tcp dpt:1214 reject-with icmp-port-unreachable
DROP       tcp  --  anywhere             anywhere            tcp spt:4444
DROP       tcp  --  anywhere             anywhere            tcp dpt:153
DROP       tcp  --  anywhere             anywhere            tcp dpt:707
DROP       tcp  --  anywhere             anywhere            tcp flags:FIN,SYN,RST,PSH,ACK,URG/SYN

Chain FORWARD (policy DROP)
target     prot opt source               destination
DROP       tcp  --  anywhere             anywhere            tcp spts:netbios-ns:netbios-ssn
DROP       udp  --  anywhere             anywhere            udp spts:netbios-ns:netbios-ssn

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination
ACCEPT     all  --  anywhere             anywhere
ACCEPT     all  --  anywhere             anywhere            state RELATED,ESTABLISHED
DROP       tcp  --  anywhere             anywhere            tcp spt:31337 dpt:31337