Linux Di Virtualbox: Basic Firewall With IPTABLES

Quick cheat sheet common IPTABLES function, I often forget, so I list here :).

To turn IPTABLES on every boot automaticaly: /sbin/chkconfig iptables on

To check status IPTABLES: iptables -L
To delete all parameters in IPTABLES: iptables -D

# Drop ICMP echo-request messages sent to broadcast or multicast addresses
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

# Drop source routed packets
echo 0 > /proc/sys/net/ipv4/conf/all/accept_source_route

# Enable TCP SYN cookie protection from SYN floods
echo 1 > /proc/sys/net/ipv4/tcp_syncookies

# Reject ICMP redirect messages, system will not reply when get ping
echo 0 > /proc/sys/net/ipv4/conf/all/accept_redirects

# Reject ICMP redirect messages
echo 0 > /proc/sys/net/ipv4/conf/all/send_redirects

# Enable source address spoofing protection, any package that pretend from internal network will be rejected
echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter

# Log packets with impossible source addresses
echo 1 > /proc/sys/net/ipv4/conf/all/log_martians
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