Abaixo estão as configurações de meu firewall e quando ponho essas regras pra rodarem, não consigo ter acesso a internet nem pelo servidor. Me ajudem.
#Start Serv
#Escript de Firewall e Roteamento de portas
#
#Apaga Regras pre Definidas
iptables -F
iptables -t nat -F
#
#APAGANDO REGRAS
iptables -F INPUT
iptables -F FORWARD
iptables -F OUTPUT
iptables -X
iptables -A INPUT -i lo -j ACCEPT
iptables -A FORWARD -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
#
#adicionando modulos
modprobe ip_conntrack
modprobe ipt_MASQUERADE
modprobe ipt_LOG
modprobe iptable_nat
modprobe ip_nat_ftp
modprobe iptable_filter
#
#Habilita o Roteamento de Kernel
echo 1 > /proc/sys/net/ipv4/ip_forward
#
#Protecao contra IP spoofing
echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter
#
#Habilita (NAT)
iptables -t nat -A POSTROUTING -s 192.168.172.0/24 -o eth0 -j MASQUERADE
#
#Redireciona Todas as portas para a 8080 (http) (Squid)
iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 80 -j REDIRECT --to 8080
#
# Dropa pacotes TCP indesejaveis
# -------------------------------------------------------
iptables -A FORWARD -p tcp ! --syn -m state --state NEW -j LOG --log-level 6 --log-prefix "FIREWALL: NEW sem syn: "
iptables -A FORWARD -p tcp ! --syn -m state --state NEW -j DROP
#
# Protecao contra syn-flood
# -------------------------------------------------------
iptables -A FORWARD -p tcp --syn -m limit --limit 2/s -j ACCEPT
#
#Protecao contra ping da morte
# -------------------------------------------------------
iptables -A FORWARD -p icmp --icmp-type echo-request -m limit --limit 1/s -j ACCEPT
#
#-------------------- CONTROLA TODAS AS INPUT NO SERVIDOR ---------------------
#
#Libera as portas para entrada no servidor
#
iptables -A INPUT -p tcp -s 192.168.172.0/24 --dport 53 -j ACCEPT
iptables -A INPUT -p udp -s 192.168.172.0/24 --dport 53 -j ACCEPT
iptables -A INPUT -p tcp -s 192.168.172.0/24 --dport 8080 -j ACCEPT
iptables -A INPUT -p tcp -s 192.168.172.0/24 --dport 80 -j ACCEPT
iptables -A INPUT -p tcp -s 192.168.172.0/24 --dport 25 -j ACCEPT
iptables -A INPUT -p tcp -s 192.168.172.0/24 --dport 110 -j ACCEPT
iptables -A INPUT -p tcp -s 192.168.172.0/24 --dport 137:139 -j ACCEPT
iptables -A INPUT -p udp -s 192.168.172.0/24 --dport 137:139 -j ACCEPT
#Mantem a conexao das portas liberada acima
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
#--------------------- CONTROLA TODOS OS FORWARD NO SERVIDOR ------------------
#
#libera as portas para passar pelo servidor e ter acesso externo
iptables -A FORWARD -s 192.168.172.0/24 -i eth1 -j ACCEPT
iptables -A FORWARD -p tcp -s 192.168.172.0/24 --dport 25 -j ACCEPT
iptables -A FORWARD -p tcp -s 192.168.172.0/24 --dport 110 -j ACCEPT
iptables -A FORWARD -p tcp -s 192.168.172.0/24 --dport 80 -j ACCEPT
#Mantem a conexao das portas acima liberada
iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
#Portas Bloqueadas (MSN)
iptables -A FORWARD -p TCP --dport 1863 -j DROP
iptables -A FORWARD -d 64.4.13.0/24 -j REJECT