Hello, I have a firewall in front of an Exchange serveur. I can't receive any mail from outside. It seems I have a problem with my script. When I do a telnet on my server on port 25, from the outside, there is a connection but this one is closed before I reach the HELO messages. Moreover, when I try to connect friom the firewall to the SMTP server( telnet 25) I have more or less the message: " escape caracter is :^] Connection closed by foreign host " My network is : Internet | | | Firewall | | SMTP Internet-Firewall interface: eth0 ip adress xxx.yyy.zzz.ttt corresponding to the MX Firewall-SMTP= eth1 SMTP: 192.168.0.2 Any idea? Here is the script: #!/bin/sh # script /etc/firewall.sh echo 1 > /proc/sys/net/ipv4/ip_forward echo "Activation du forwarding :[OK]\n" if [ -e /proc/sys/net/ipv4/conf/all/rp_filter ] then for filtre in /proc/sys/net/ipv4/conf/*/rp_filter do echo 1 > $filtre done fi echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts modprobe ip_tables modprobe iptable_filter modprobe iptable_nat iptables -F iptables -X iptables -N LOG_DROP iptables -A LOG_DROP -j LOG --log-prefix '[IPTABLES DROP] : ' iptables -A LOG_DROP -j DROP iptables -N LOG_ACCEPT iptables -A LOG_ACCEPT -j LOG --log-prefix '[IPTABLES ACCEPT] : ' iptables -A LOG_ACCEPT -j ACCEPT iptables -P INPUT DROP iptables -P OUTPUT DROP iptables -P FORWARD DROP iptables -A INPUT -i lo -j ACCEPT iptables -A OUTPUT -o lo -j ACCEPT iptables -A OUTPUT -o eth0 -m state --state NEW,ESTABLISHED -p tcp --dport 80 -j ACCEPT iptables -A INPUT -i eth0 -m state --state ESTABLISHED -p tcp --sport 80 -j ACCEPT iptables -A OUTPUT -o eth0 -m state --state NEW,ESTABLISHED -p tcp --dport 80 -j ACCEPT iptables -A INPUT -i eth0 -m state --state ESTABLISHED -p tcp --sport 80 -j ACCEPT iptables -t nat -A PREROUTING -d xxx.yyy.zzz.ttt -p tcp --dport 80 -j DNAT --to-destination 192.168.0.2:80 iptables -t nat -A PREROUTING -d xxx.yyy.zzz.ttt -p tcp --dport 25 -j DNAT --to-destination 192.168.0.2:25 iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT iptables -A FORWARD -o eth1 -i eth0 -j ACCEPT iptables -A FORWARD -i eth0 -o eth1 -p tcp --destination-port 80 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A FORWARD -o eth0 -i eth1 -p tcp --source-port 80 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A FORWARD -i eth0 -o eth1 -p tcp --destination-port 25 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A FORWARD -o eth0 -i eth1 -p tcp --source-port 25 -m state --state ESTABLISHED -j ACCEPT iptables -A FORWARD -j LOG_DROP iptables -A INPUT -j LOG_DROP iptables -A OUTPUT -j LOG_DROP
