CentOS 7 下配置ip forward(虚拟路由器)

阳光穿透心脏的1/2处 2022-06-08 14:42 261阅读 0赞

Linux 中ip forward功能是一个比较方便实用的功能，只需要简单配置，添加几条路由，即可实现ip转发。本文基于CentOS 7下采取一台机器充当虚拟路由，来实现Windows环境与Linux环境中相互通信。具体见下文，供大家参考。

## 一、环境及需求说明 ##

![这里写图片描述][SouthEast]

本地测试环境，由于Win7+VMware这台机器网卡太新，无法被VMware EXSi识别，无奈之下就直接装了个Win7，然后再上面基于Vmware workstation 12开启了一些临时测试的虚拟机。其次本地直连网段192.168.1.0 IP有限，而又希望直接从本机(如图Win10) ssh连接到这些虚拟机，因此考虑使用Linux的ip转发功能来实现。  
上述图片中已经列出了各个节点的IP信息，红色的虚拟机充当软路由，配置好之后，实现Win10 直接ssh到虚拟机。

## 二、虚拟路由服务器配置 ##

###查看网卡信息
    [root@centos7-router ~]# ip addr
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
        link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
        inet 127.0.0.1/8 scope host lo
          valid_lft forever preferred_lft forever
        inet6 ::1/128 scope host 
          valid_lft forever preferred_lft forever
    2: eno16777728: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
        link/ether 00:0c:29:9c:eb:2d brd ff:ff:ff:ff:ff:ff
        inet 172.24.8.254/24 brd 172.24.8.255 scope global eno16777728
          valid_lft forever preferred_lft forever
        inet6 fe80::20c:29ff:fe9c:eb2d/64 scope link 
          valid_lft forever preferred_lft forever
    3: eno33554960: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
        link/ether 00:0c:29:9c:eb:37 brd ff:ff:ff:ff:ff:ff
        inet 192.168.1.175/24 brd 192.168.1.255 scope global dynamic eno33554960
          valid_lft 82384sec preferred_lft 82384sec
        inet6 fe80::20c:29ff:fe9c:eb37/64 scope link 
          valid_lft forever preferred_lft forever
    
    ###查看路由表
    [root@centos7-router ~]# route -n
    Kernel IP routing table  ###缺省情况下，每块网卡都有一个基于本网段的路由记录
    Destination    Gateway        Genmask        Flags Metric Ref    Use Iface
    0.0.0.0        192.168.1.1    0.0.0.0        UG    100    0        0 eno33554960
    172.24.8.0      0.0.0.0        255.255.255.0  U    100    0        0 eno16777728
    192.168.1.0    0.0.0.0        255.255.255.0  U    100    0        0 eno33554960
    
    ###使用ip命令方式查看路由
    [root@centos7-router ~]# ip route list
    default via 192.168.1.1 dev eno33554960  proto static  metric 100 
    172.24.8.0/24 dev eno16777728  proto kernel  scope link  src 172.24.8.254  metric 100 
    192.168.1.0/24 dev eno33554960  proto kernel  scope link  src 192.168.1.175  metric 100  
    
    ###开启ip forward
    [root@centos7-router ~]# cp /usr/lib/sysctl.d/50-default.conf /usr/lib/sysctl.d/50-default.conf.bk
    [root@centos7-router ~]# echo "net.ipv4.ip_forward = 1" >>/usr/lib/sysctl.d/50-default.conf
    [root@centos7-router ~]# grep ip_forward /usr/lib/sysctl.d/50-default.conf
    net.ipv4.ip_forward = 1
    [root@centos7-router ~]# sysctl -p ###如不生效重启一下OS

## 三、CentOS7-a主机下添加路由 ##

###查看当前主机ip 信息
    [root@centos7-a ~]# ip addr list
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
        link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
        inet 127.0.0.1/8 scope host lo
          valid_lft forever preferred_lft forever
        inet6 ::1/128 scope host 
          valid_lft forever preferred_lft forever
    2: eno16777728: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
        link/ether 00:0c:29:57:26:9d brd ff:ff:ff:ff:ff:ff
        inet 172.24.8.131/24 brd 172.24.8.255 scope global dynamic eno16777728
          valid_lft 1088sec preferred_lft 1088sec
        inet6 fe80::20c:29ff:fe57:269d/64 scope link 
          valid_lft forever preferred_lft forever
    
    ###查看当前主机路由信息 
    [root@centos7-a ~]# ip route list
    172.24.8.0/24 dev eno16777728  proto kernel  scope link  src 172.24.8.131  metric 100 
    
    [root@centos7-a ~]# # Author : Leshami
    [root@centos7-a ~]# # Blog : http://blog.csdn.net/leshami
    [root@centos7-a ~]# ip route add default via 172.24.8.254
    [root@centos7-a ~]# ip route list
    default via 172.24.8.254 dev eno16777728 
    172.24.8.0/24 dev eno16777728  proto kernel  scope link  src 172.24.8.131  metric 100 
    
    ###测试到虚拟路由器网关ip连通性
    [root@centos7-a ~]# ping 172.24.8.254 -c 2 
    PING 172.24.8.254 (172.24.8.254) 56(84) bytes of data.
    64 bytes from 172.24.8.254: icmp_seq=1 ttl=64 time=0.268 ms
    64 bytes from 172.24.8.254: icmp_seq=2 ttl=64 time=0.302 ms
    
    --- 172.24.8.254 ping statistics ---
    2 packets transmitted, 2 received, 0% packet loss, time 1000ms
    rtt min/avg/max/mdev = 0.268/0.285/0.302/0.017 ms
    
    ###测试到虚拟路由器ip连通性
    [root@centos7-a ~]# ping 192.168.1.175 -c 2
    PING 192.168.1.175 (192.168.1.175) 56(84) bytes of data.
    64 bytes from 192.168.1.175: icmp_seq=1 ttl=64 time=0.475 ms
    64 bytes from 192.168.1.175: icmp_seq=2 ttl=64 time=0.443 ms
    
    --- 192.168.1.175 ping statistics ---
    2 packets transmitted, 2 received, 0% packet loss, time 1000ms
    rtt min/avg/max/mdev = 0.443/0.459/0.475/0.016 ms

## 四、Windows 10下配置路由 ##

###当前环境
    C:\>systeminfo | findstr Build
    OS Version:                10.0.14393 N/A Build 14393
    OS Build Type:            Multiprocessor Free
    
    ###查看当前的路由信息
    C:\>route print -4 ===========================================================================
    Interface List
     7...54 ab 3a xx b8 ea ......Intel(R) Ethernet Connection I219-V
    21...ac 2b 6e 5f 3b 57 ......Microsoft Wi-Fi Direct Virtual Adapter
     ...... ===========================================================================
    IPv4 Route Table ===========================================================================
    Active Routes:
    Network Destination        Netmask          Gateway      Interface  Metric
     0.0.0.0 0.0.0.0 192.168.1.1 192.168.1.242 35
     127.0.0.0 255.0.0.0 On-link 127.0.0.1 331
     127.0.0.1 255.255.255.255 On-link 127.0.0.1 331
     127.255.255.255 255.255.255.255 On-link 127.0.0.1 331
     172.24.10.0 255.255.255.0 On-link 172.24.10.1 291
     172.24.10.1 255.255.255.255 On-link 172.24.10.1 291
     172.24.10.255 255.255.255.255 On-link 172.24.10.1 291
     192.168.1.0 255.255.255.0 On-link 192.168.1.242 291
     192.168.1.242 255.255.255.255 On-link 192.168.1.242 291
     192.168.1.255 255.255.255.255 On-link 192.168.1.242 291
     192.168.16.0 255.255.255.0 On-link 192.168.16.1 291
     192.168.16.1 255.255.255.255 On-link 192.168.16.1 291
     192.168.16.255 255.255.255.255 On-link 192.168.16.1 291
     224.0.0.0 240.0.0.0 On-link 127.0.0.1 331
     224.0.0.0 240.0.0.0 On-link 192.168.1.242 291
     224.0.0.0 240.0.0.0 On-link 192.168.16.1 291
     224.0.0.0 240.0.0.0 On-link 172.24.10.1 291
     255.255.255.255 255.255.255.255 On-link 127.0.0.1 331
     255.255.255.255 255.255.255.255 On-link 192.168.1.242 291
     255.255.255.255 255.255.255.255 On-link 192.168.16.1 291
     255.255.255.255 255.255.255.255 On-link 172.24.10.1 291 ===========================================================================
    Persistent Routes:
     None
    
    ###添加持久化路由  
    C:\>route add 172.24.8.0 mask 255.255.255.0 192.168.1.175 -p
    OK!
    
    C:\>route print -4
    
    IPv4 Route Table ===========================================================================
    Active Routes:
    Network Destination        Netmask          Gateway      Interface  Metric
     0.0.0.0 0.0.0.0 192.168.1.1 192.168.1.242 35
     127.0.0.0 255.0.0.0 On-link 127.0.0.1 331
     127.0.0.1 255.255.255.255 On-link 127.0.0.1 331
     127.255.255.255 255.255.255.255 On-link 127.0.0.1 331
     172.24.8.0 255.255.255.0 192.168.1.175 192.168.1.242 36
     172.24.10.0 255.255.255.0 On-link 172.24.10.1 291
     172.24.10.1 255.255.255.255 On-link 172.24.10.1 291
     172.24.10.255 255.255.255.255 On-link 172.24.10.1 291
     192.168.1.0 255.255.255.0 On-link 192.168.1.242 291
     192.168.1.242 255.255.255.255 On-link 192.168.1.242 291
     192.168.1.255 255.255.255.255 On-link 192.168.1.242 291
     192.168.16.0 255.255.255.0 On-link 192.168.16.1 291
     192.168.16.1 255.255.255.255 On-link 192.168.16.1 291
     192.168.16.255 255.255.255.255 On-link 192.168.16.1 291
     224.0.0.0 240.0.0.0 On-link 127.0.0.1 331
     224.0.0.0 240.0.0.0 On-link 192.168.1.242 291
     224.0.0.0 240.0.0.0 On-link 192.168.16.1 291
     224.0.0.0 240.0.0.0 On-link 172.24.10.1 291
     255.255.255.255 255.255.255.255 On-link 127.0.0.1 331
     255.255.255.255 255.255.255.255 On-link 192.168.1.242 291
     255.255.255.255 255.255.255.255 On-link 192.168.16.1 291
     255.255.255.255 255.255.255.255 On-link 172.24.10.1 291 ===========================================================================
    Persistent Routes:  ###以下为添加的持久化路由记录
     Network Address Netmask Gateway Address Metric
     172.24.8.0 255.255.255.0 192.168.1.175 1 ===========================================================================

## 五、验证两边连通性 ##

###从Linux端ping windows 10
    [root@centos7-a ~]# ping 192.168.1.242 -c 2 
    PING 192.168.1.242 (192.168.1.242) 56(84) bytes of data.
    64 bytes from 192.168.1.242: icmp_seq=1 ttl=63 time=1.70 ms
    64 bytes from 192.168.1.242: icmp_seq=2 ttl=63 time=1.10 ms
    
    --- 192.168.1.242 ping statistics ---
    2 packets transmitted, 2 received, 0% packet loss, time 1002ms
    rtt min/avg/max/mdev = 1.101/1.404/1.707/0.303 ms
    
    ###从windows 10端ping Linux
    C:\>ping 172.24.8.131 -t
    
    Pinging 172.24.8.131 with 32 bytes of data:
    Reply from 172.24.8.131: bytes=32 time=1ms TTL=63
    Reply from 172.24.8.131: bytes=32 time=1ms TTL=63
    
    注，如果测试有问题，请考虑是否被防火墙拦住。

[![DBA牛鹏社(SQL/NOSQL/LINUX)][DBA_SQL_NOSQL_LINUX]][DBA_SQL_NOSQL_LINUX_DBA_SQL_NOSQL_LINUX]

![这里写图片描述][1493001734_6055.jpg]

[SouthEast]: /images/20220608/9d04a29dbdba4d39a7937f709607852d.png
[DBA_SQL_NOSQL_LINUX]: http://pub.idqqimg.com/wpa/images/group.png
[DBA_SQL_NOSQL_LINUX_DBA_SQL_NOSQL_LINUX]: /images/20220608/5a4049fa083a413d9fe455bcab3ce39d.png
[1493001734_6055.jpg]: https://img-my.csdn.net/uploads/201704/24/1493001734_6055.jpg