通过能别的主机连接yum库

本地有两台主机，分别为：192.168.2.131/24和192.168.2.132/24，本地yum源只能连接互联网；

这两台设备的虚拟机配置如下：

现有一台主机：172.16.254.88/16可连接互联网，如何完成上面两台主机的yum里包的安装！

#首先测试192.168.2.131和132是不是可以通信；
[root@~ pxe99]#ping 192.168.2.131
PING 192.168.2.131 (192.168.2.131) 56(84) bytes of data.
64 bytes from 192.168.2.131: icmp_seq=1 ttl=64 time=9.68 ms
64 bytes from 192.168.2.131: icmp_seq=2 ttl=64 time=1.75 ms
^C
--- 192.168.2.131 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1002ms
rtt min/avg/max/mdev = 1.752/5.716/9.680/3.964 ms
[root@~ localhost]#route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.2.0     0.0.0.0         255.255.255.0   U     100    0        0 eno16777736

#添加172那台主机的路由
[root@~ localhost]#route add -net default gw 192.168.2.133
[root@~ localhost]#route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.2.133   0.0.0.0         UG    0      0        0 eno16777736
192.168.2.0     0.0.0.0         255.255.255.0   U     100    0        0 eno16777736
[root@~ localhost]#ping 192.168.2.133
PING 192.168.2.133 (192.168.2.133) 56(84) bytes of data.
64 bytes from 192.168.2.133: icmp_seq=1 ttl=64 time=13.7 ms
64 bytes from 192.168.2.133: icmp_seq=2 ttl=64 time=4.89 ms
^C
--- 192.168.2.133 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1008ms
rtt min/avg/max/mdev = 4.898/9.310/13.723/4.413 ms
[root@~ localhost]#ping 172.16.254.88
PING 172.16.254.88 (172.16.254.88) 56(84) bytes of data.
64 bytes from 172.16.254.88: icmp_seq=1 ttl=64 time=25.2 ms
64 bytes from 172.16.254.88: icmp_seq=2 ttl=64 time=2.47 ms
^C
--- 172.16.254.88 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1002ms
rtt min/avg/max/mdev = 2.472/13.847/25.223/11.376 ms
#得知可以连同；另一台131也这么配置

#在主机172上添加IPtables的nat策略
[root@~ localhost]#iptables -F
[root@~ localhost]#iptables -t nat -A POSTROUTING -s 192.168.2.0/24 -j SNAT --to-source 172.16.254.88
#在192主机开始安装
[root@~ pxe99]#yum -y install httpd telnet-server tftp-server