请问在linux下如何用两块网卡配置成网关?

LinuxBadGuy

如题

linky_fan

能不能说的明白一点

dannycat

如果两面都是真实IP的话，开 ip_forward 就OK了。

xjtuboy

把下面的东西copy到rc.local里面.
eth0对应外网,eth1对应内网,根据你的情况相应修改.



# To use iptables-based NAT, we must enable IP forwarding for IPv4:
echo 1 > /proc/sys/net/ipv4/ip_forward
# Or modify /etc/sysctl.conf such that:
# net.ipv4.ip_forward = 1

# IPTABLES firewall
# extdev: the network device/interface for the external network
# intdev: the network device/interface for the internal network
extdev=eth0
intdev=eth1

# extip: the IP of the external network
# intranet: the network ID of the internal network
# Manually assign the value of extip or intranet:
#extip=20.30.40.50
#intranet=192.168.9.0/24
# Or extract the value from output of ifconfig:
extip=`/sbin/ifconfig $extdev | grep inet | cut -d : -f 2 | cut -d ' ' -f 1`
intranet=`/sbin/ifconfig $intdev | grep inet | cut -d : -f 2  | cut -d ' ' -f  1 | cut -d . -f 1-3`.0/24

/sbin/modprobe ip_tables
/sbin/modprobe ip_conntrack_ftp
/sbin/modprobe ip_nat_ftp
/sbin/iptables -F
/sbin/iptables -F -t nat
/sbin/iptables -P INPUT    ACCEPT
/sbin/iptables -P OUTPUT   ACCEPT
/sbin/iptables -P FORWARD  DROP
/sbin/iptables -A INPUT   -s $intranet -i $extdev -j DROP
/sbin/iptables -A FORWARD -s $intranet -i ! $extdev -o $extdev -j ACCEPT
/sbin/iptables -A FORWARD -i $extdev -o ! $extdev -m state --state ESTABLISHED,RELATED -j ACCEPT
/sbin/iptables -t nat -A POSTROUTING -s $intranet -o $extdev -j SNAT --to-source $extip