Generic iptables rules template, ready to be used;-)

iptables.rules

*filter
# Allow all loopback (lo) traffic and drop all traffic to 127.0.0.0/8 that doesn't use lo
-A INPUT -i lo -j ACCEPT
-A INPUT -d 127.0.0.0/8 -j REJECT
# Accept all established inbound connections
# -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
# conntrack match is recommended 
-A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
# Allow all outbound traffic
# It can be modified to allow certain traffic ONLY
-A OUTPUT -j ACCEPT
# Allow SSH connections
# The -dport number should be the same port number set in sshd_config
# -A INPUT -p tcp -m state --state NEW --dport 22 -j ACCEPT
-A INPUT -p tcp -m conntrack --ctstate NEW --dport 22 -j ACCEPT
# -A INPUT -p tcp --dport 22 -j ACCEPT
# Allow HTTP and HTTPS connections from anywhere
-A INPUT -p tcp --dport 80 -j ACCEPT
# -A INPUT -p tcp --dport 443 -j ACCEPT
# Allow ping
-A INPUT -p icmp -j ACCEPT
# Log iptables denied calls
# -A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7
# Drop all other inbound - default deny unless explicitly allowed policy
# -A INPUT -j DROP
-P INPUT DROP
# -A FORWARD -j DROP
# -P FORWARD DROP
COMMIT