使用 fwmark 将子网路由到特定路由表，直接到 ISP 和 VPN

Question

我终于找到了解决这个问题的方法。

首先，与上一个问题一样，编辑并添加到/etc/iproute2/rt_tables

1 ISP
2 VPN

接下来添加到/etc/网络/接口

auto eth0:2
iface eth0:2 inet static
    address 192.168.2.1
    netmask 255.255.255.0
    post-up /etc/network/fwmark_rules

创建文件/etc/network/fwmark_rules这里我们列出 fwmark 规则：

#!/bin/sh

# Normal packets to go direct out WAN
/sbin/ip rule add fwmark 1 table ISP prio 100

# Put packets destined into VPN when VPN is up
/sbin/ip rule add fwmark 2 table VPN prio 200

# Prevent packets from being routed out when VPN is down.
# This prevents packets from falling back to the main table
# that has a priority of 32766
/sbin/ip rule add prohibit fwmark 2 prio 300

如果 VPN 因优先级低于 32766 而发生故障，禁止行可防止表 VPN 中的事物回退到主服务器。您可以在4.9. 路由策略数据库（RPDB）

添加/etc/ppp/ip-up。这是我们放置 PPP 连接上线时的 IP 规则的地方。

#!/bin/sh
#
# This script is run by pppd when there's a successful ppp connection.
#

# Flush out any old rules that might be there
/sbin/ip route flush table ISP

# Add route to table from subnets on LAN
/sbin/ip route add 192.168.1.0/24 dev eth0 table ISP prio 100
/sbin/ip route add 192.168.2.0/24 dev eth0 table ISP prio 200

# Add route from IP given by ISP to the table
/sbin/ip rule add from ${IPLOCAL} table ISP prio 100

# Add a default route
/sbin/ip route add table ISP default via ${IPLOCAL} prio 100

确保添加/etc/ppp/ip-down这是我们在接口关闭时删除规则的地方，这样我们就不会得到重复。您可以在pppd man 文件 - 脚本

#!/bin/sh
#
# This script is run by pppd after the connection has ended.
#

# Delete the rules when we take the interface down
/sbin/ip rule del from ${IPLOCAL} table ISP prio 100

现在我们需要为 OpenVPN 创建路由脚本。因此编辑/etc/openvpn/route-up-fwmark.shOpenVPN也有特殊的环境变量OpenVPN-环境变量）

#!/bin/sh
#
# This script is run by OpenVPN when there's a successful VPN connection.
#

# Flush out any old rules that might be there
/sbin/ip route flush table VPN

# Add route to table from 192.168.2.0/24 subnet on LAN
/sbin/ip route add 192.168.2.0/24 dev eth0 table VPN prio 200

# Add route from VPN interface IP to the VPN table
/sbin/ip rule add from ${ifconfig_local} table VPN prio 200

# Add a default route
/sbin/ip route add default via ${ifconfig_local} dev ${dev} table VPN prio 200

在接口关闭之前删除规则/etc/openvpn/route-pre-down-fwmark.sh

#!/bin/sh
#
# This script is run by OpenVPN after the connection has ended
#

# Delete the rules when we take the interface down
/sbin/ip rule del from ${ifconfig_local} table VPN prio 200

最后你的 mangle 表应该如下所示：

*mangle

# Set default policies for table
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]

# Restore CONNMARK to the MARK (If one doesn't exist then no mark is set)
-A PREROUTING -j CONNMARK --restore-mark --nfmask 0xffffffff --ctmask 0xffffffff

# If packet MARK is 2, then it means there is already a connection mark and the original packet came in on VPN
-A PREROUTING -s 192.168.2.0/24 -m mark --mark 0x2 -j ACCEPT

# Check exception (this is a server which when accessed on a 192.168.2.0/24 address will go out the ISP table) are 0x1
#-A PREROUTING -s 192.168.2.0/24 -d <IP_OF_EXCEPTED_SERVER>/32 -m mark --mark 0x1 -j ACCEPT

# Check packets coming from 192.168.2.0/24 are 0x2
-A PREROUTING -s 192.168.2.0/24 -j MARK --set-xmark 0x2/0xffffffff

# If packet MARK is 1, then it means there is already a connection mark and the original packet came in on ISP
-A PREROUTING -s 192.168.1.0/24 -m mark --mark 0x1 -j ACCEPT

# Check packets coming from 192.168.1.0/24 are 0x1
-A PREROUTING -s 192.168.1.0/24 -j MARK --set-xmark 0x1/0xffffffff

# Mark exception (this is a server which when accessed on a 192.168.2.0/24 address will go out the ISP table) as 0x1
#-A PREROUTING -s 192.168.2.0/24 -d <IP_OF_EXCEPTED_SERVER>/32 -j MARK --set-xmark 0x1/0xffffffff

# Save MARK to CONNMARK (remember iproute can't see CONNMARKs)
-A PREROUTING -j CONNMARK --save-mark --nfmask 0xffffffff --ctmask 0xffffffff
COMMIT

您还需要编辑/etc/openvpn/openvpn.conf并添加

# Prevents default gateway from being set on the default routing table
route-noexec

# Allows route-up script to be executed
script-security 2

# Calls custom shell script after connection to add necessary routes
route-up /etc/openvpn/route-up-fwmark.sh
route-pre-down /etc/openvpn/route-pre-down-fwmark.sh

Answer 1