nao sei qual eh uh problema por ai amigo mais vai uns script aqui pra ve se ajuda

------------------------------INICIO-----------------------------------------------
#!/bin/sh

case "$1" in
start)
echo 0 > /proc/sys/net/ipv4/conf/all/accept_redirects
echo 0 > /proc/sys/net/ipv4/conf/all/accept_source_route
echo 0 > /proc/sys/net/ipv4/conf/all/log_martians
echo 30 > /proc/sys/net/ipv4/tcp_fin_timeout
echo 0 > /proc/sys/net/ipv4/tcp_window_scaling
echo 1800 > /proc/sys/net/ipv4/tcp_keepalive_time
echo 0 > /proc/sys/net/ipv4/tcp_timestamps
echo 0 > /proc/sys/net/ipv4/tcp_sack
echo 1024 > /proc/sys/net/ipv4/tcp_max_syn_backlog
echo 1 > /proc/sys/net/ipv4/ip_forward
echo 1 > /proc/sys/net/ipv4/ip_dynaddr
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
echo 1 > /proc/sys/net/ipv4/icmp_ignore_bogus_error_responses
;;
stop)
echo 0 > /proc/sys/net/ipv4/conf/all/accept_redirects
echo 0 > /proc/sys/net/ipv4/conf/all/accept_source_route
echo 0 > /proc/sys/net/ipv4/conf/all/log_martians
echo 30 > /proc/sys/net/ipv4/tcp_fin_timeout
echo 1 > /proc/sys/net/ipv4/tcp_window_scaling
echo 1800 > /proc/sys/net/ipv4/tcp_keepalive_time
echo 1 > /proc/sys/net/ipv4/tcp_timestamps
echo 1 > /proc/sys/net/ipv4/tcp_sack
echo 1024 > /proc/sys/net/ipv4/tcp_max_syn_backlog
echo 0 > /proc/sys/net/ipv4/ip_forward
echo 1 > /proc/sys/net/ipv4/ip_dynaddr
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
echo 1 > /proc/sys/net/ipv4/icmp_ignore_bogus_error_responses
;;
*)
echo "Uso: $0 {start|stop}"
exit 1
;;
esac

exit 0

------------------------------FIM----------------------------------------------------

------------------------------INICIO-----------------------------------------------
#!/bin/sh

case "$1" in
start)
/sbin/iptables -F
/sbin/iptables -X
/sbin/iptables -t nat -F
/sbin/iptables -t nat -X
/sbin/iptables -P INPUT DROP
/sbin/iptables -P FORWARD DROP
/sbin/iptables -P OUTPUT ACCEPT
/sbin/iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -j MASQUERADE
/sbin/iptables -A INPUT -i lo -j ACCEPT
/sbin/iptables -A INPUT -p tcp --dport 22 -j ACCEPT
/sbin/iptables -A FORWARD -p tcp --dport 21 -j ACCEPT
/sbin/iptables -A FORWARD -p tcp --dport 22 -j ACCEPT
/sbin/iptables -A FORWARD -p tcp --dport 25 -j ACCEPT
/sbin/iptables -A FORWARD -p udp --dport 53 -j ACCEPT
/sbin/iptables -A FORWARD -p tcp --dport 80 -j ACCEPT
/sbin/iptables -A FORWARD -p tcp --dport 110 -j ACCEPT
/sbin/iptables -A FORWARD -p tcp --dport 143 -j ACCEPT
;;
stop)
/sbin/iptables -F
/sbin/iptables -X
/sbin/iptables -P INPUT DROP
/sbin/iptables -P FORWARD DROP
/sbin/iptables -P OUTPUT DROP
;;
reset)
/sbin/iptables -Z
/sbin/iptables -t nat -Z
;;
*)
echo "Uso: $0 {start,stop,reset}"
exit 1
;;
esac

exit 0
------------------------------FIM----------------------------------------------------

Abri somente a porta 53 UDP pq a resolucao de nomes e por UDP <IMG SRC="images/forum/icons/icon_wink.gif">