*filter # Allows all loopback (lo0) traffic and drop all traffic to 127/8 that doesnot use lo0 -A INPUT -i lo -j ACCEPT -A INPUT -i ! lo -d 127.0.0.0/8 -j REJECT # Accepts all established inbound connections -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT # Allows all outbound traffic # You can modify this to only allow certain traffic -A OUTPUT -j ACCEPT # Accept responses to DNS queries -A INPUT -p udp -m udp --dport 1024:65535 --sport 53 -j ACCEPT # Allows HTTP and HTTPS connections from anywhere (the normal ports for websites) # -A INPUT -p tcp --dport 80 -j ACCEPT # -A INPUT -p tcp --dport 443 -j ACCEPT -A INPUT -p udp --dport 53 -j ACCEPT # Allows SSH connections # THE -dport NUMBER IS THE SAME ONE YOU SET UP IN THE SSHD_CONFIG FILE -A INPUT -p tcp -m state --state NEW --dport ssh -j ACCEPT # Allow ping -A INPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT # log iptables denied calls -A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7 # Reject all other inbound - default deny unless explicitly allowed policy -A INPUT -j REJECT -A FORWARD -j REJECT COMMIT ------------------------------------------------------------------------------------- sp4635b:/# iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination ACCEPT 0 -- anywhere anywhere REJECT 0 -- anywhere loopback/8 reject-with icmp-port-unreachable ACCEPT 0 -- anywhere anywhere state RELATED,ESTABLISHED ACCEPT udp -- anywhere anywhere udp spt:domain dpts:1024:65535 ACCEPT udp -- anywhere anywhere udp dpt:domain ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:ssh ACCEPT icmp -- anywhere anywhere icmp echo-request LOG 0 -- anywhere anywhere limit: avg 5/min burst 5 LOG level debug prefix `iptables denied: ' REJECT 0 -- anywhere anywhere reject-with icmp-port-unreachable Chain FORWARD (policy ACCEPT) target prot opt source destination REJECT 0 -- anywhere anywhere reject-with icmp-port-unreachable Chain OUTPUT (policy ACCEPT) target prot opt source destination ACCEPT 0 -- anywhere anywhere ---------------------------------------------------------------------------------------------- why does port 53 not show open when i scan with nmap