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Well, this isn't a security issue per se, but I am curious about a few things. I only run a webserver, so my iptables firewall drops everything not destined for port 80, however, when I run nmap it shows 3306 mysql as open.
I do use mysql, but it is on the same computer so I don't need the port open right?
Why does port 3306 ignore my firewall rules? Anyone know what's up?
You might want to post your iptables script to get a better answer. However, I'll hazard the guess that your script isn't blocking internal requests. In other words, if you used nmap to scan from a different computer, you might not see port 3306 open.
Of course without seeing your iptables rules, this is nothing more than a WAG.
# set a sane policy: everything not accepted > /dev/null
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT DROP
# allow local-only connections
iptables -A INPUT -i lo -j ACCEPT
# free output on any interface to any ip for any service (equal to -P ACCEPT)
iptables -A OUTPUT -j ACCEPT
# permit answers on already established connections
# and permit new connections related to established ones (eg active-ftp)
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
# accepts http requests at port 80
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
Perhaps you could scan me to see...my domain is in my sig