and stealth specific ports?
To deny responses to ping requests..Add the following iptable rule
iptables -A OUTPUT -p icmp -o eth0 -j ACCEPT iptables -A INPUT -p icmp --icmp-type echo-reply -s 0/0 -i eth0 -j ACCEPT iptables -A INPUT -p icmp --icmp-type destination-unreachable -s 0/0 -i eth0 -j ACCEPT iptables -A INPUT -p icmp --icmp-type time-exceeded -s 0/0 -i eth0 -j ACCEPT iptables -A INPUT -p icmp -i eth0 -j DROP
Simplest method of disabling ping response is to add an entry in /etc/sysctl.conf file. If the Iptables flushes or stop server will start responding to ping responses again. I suggest the following entry in your /etc/sysctl.conf file
net.ipv4.icmp_echo_ignore_all = 1
this will tell kernel to not respond any ping response, after this run sysctl -p on shell to implement the changes without reboot.
For more info please refer: http://www.trickylinux.net/disable-ping-response-linux/
Drop ICMP echo requests ("Ping"):
iptables -A INPUT -p icmp --icmp-type echo-request -j DROP
What do you mean by stealth? You could just DROP all incoming packets. Google provided this:
iptables -A INPUT -p tcp -m stealth -j REJECT
But on (my) Ubuntu box, iptables does not know of a "stealth" match. As it seems, you can do lots of interesting stuff with xtables:
aptitude show xtables-addons-common