I am trying to open port 3306 (for remote mysql connections) on my ubuntu 12.04 server machine but for the life of me can't get the damned thing to work! Here is what I did: 1) list current firewall rules: $> sudo iptables -nL -v output: Chain INPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 225 16984 fail2ban-ssh tcp -- * * 0.0.0.0/0 0.0.0.0/0 multiport dports 22 220 69605 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 0 0 REJECT all -- lo * 0.0.0.0/0 127.0.0.0/8 reject-with icmp-port-unreachable 486 54824 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED 1 60 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 19 988 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:443 1 52 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 8 4 208 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 5/min burst 5 LOG flags 0 level 7 prefix "iptables denied: " 4 208 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 735 182K ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 Chain fail2ban-ssh (1 references) pkts bytes target prot opt in out source destination 225 16984 RETURN all -- * * 0.0.0.0/0 0.0.0.0/0 2) try to connect from remote machine: $> mysql -u root -p -h x.x.x.x output: timeout.... failed to connect 3) try to add a new rule to iptables: iptables -A INPUT -i eth0 -p tcp -m tcp --dport 3306 -j ACCEPT 4) make sure the new rule is added: $> sudo iptables -nL -v output: Chain INPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 359 25972 fail2ban-ssh tcp -- * * 0.0.0.0/0 0.0.0.0/0 multiport dports 22 251 78665 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 0 0 REJECT all -- lo * 0.0.0.0/0 127.0.0.0/8 reject-with icmp-port-unreachable 628 64420 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED 1 60 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 19 988 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:443 1 52 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 8 5 260 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 5/min burst 5 LOG flags 0 level 7 prefix "iptables denied: " 5 260 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable 0 0 ACCEPT tcp -- eth0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:3306 Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 919 213K ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 Chain fail2ban-ssh (1 references) pkts bytes target prot opt in out source destination 359 25972 RETURN all -- * * 0.0.0.0/0 0.0.0.0/0 which appears to be the case (last line in "Chain INPUT" section). 5) try to connect again from remote machine: $> mysql -u root -p -h x.x.x.x output: timeout.... failed to connect which is failing again. 6) try to flush all rules: $> sudo iptables -F 7) this time I CAN CONNECT. 8) reboot server and try to connect, FAILURE. I suspect since the new rule is being appended at the end it will have no effect as there appears to be a "reject all" sort of rule before it. If this is the case, how to make sure the new rule is added in the right order? Otherwise, what am I missing? Please help.