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Linux CentOS 6 NAT 轉發 完整教程
網絡拓補圖:
環境介紹:
一臺CentOS6 主機,雙網卡,兩網段
網口設定如下:
[root@CentOS?~]
#?cat?/etc/sysconfig/network-scripts/ifcfg-eth0?
DEVICE=eth0
TYPE=Ethernet
ONBOOT=
yes
BOOTPROTO=dhcp
[root@CentOS?~]
#?
?
?[root@CentOS?~]
#?cat?/etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE=eth1
TYPE=Ethernet
ONBOOT=
yes
BOOTPROTO=static
?
?IPADDR=192.168.66.1
NETMASK=255.255.255.0
?
?[root@CentOS?~]
#?service?network?restart
?
??
?[root@CentOS?~]
#?ifconfig?-a
eth0? ? ? Link?encap:Ethernet? HWaddr?00:0C:29:37:00:93?
? ? ? ? ?
inet?addr:172.16.20.183? Bcast:172.16.255.255? Mask:255.255.0.0
?
?? ? ? ? ?
?eth1? ? ? Link?encap:Ethernet? HWaddr?00:0C:29:37:00:9D?
? ? ? ? ?
inet?addr:192.168.66.1? Bcast:192.168.66.255? Mask:255.255.255.0?
?打開網卡轉發
[root@CentOS?~]
#?vim?/etc/sysctl.conf?
net.ipv4.ip_forward?=?1
立即生效
[root@CentOS?~]
#?sysctl?-p
?轉發規則:
[root@CentOS?~]
#?iptables?-t?nat?-A?POSTROUTING?-s?192.168.66.0/24?-j?SNAT?--to?172.16.20.183?#出口為靜態IP選這個
[root@CentOS?~]
#?iptables?-t?nat?-A?POSTROUTING?-s?192.168.66.0/24?-o?eth0?-j?MASQUERADE?#出口為動態IP選這個
?查看/保存轉發規則
[root@CentOS?~]
#?iptables?-t?nat?-nL
[root@CentOS?~]
#?service?iptables?save
?========驗證NAT=======?
在192.168.66/24網段內,一臺linux主機設置為:
[root@CentOS?~]
#?cat?/etc/sysconfig/network-scripts/ifcfg-eth0?
DEVICE=eth0
TYPE=Ethernet
ONBOOT=
yes
BOOTPROTO=static
?
?IPADDR=192.168.66.2
NETMASK=255.255.255.0
GATEWAY=192.168.66.1
DNS1=180.76.76.76.76
DNS2=8.8.8.8
?
?[root@CentOS?~]
#
?
??
?重啟網絡服務
[root@CentOS?~]
#?service?network?restart
Shutting?down?interface?eth0:? ? ? ? ? ? ? ? ? ? ? ? ? ? ? [? OK? ]
Shutting?down?loopback?interface:? ? ? ? ? ? ? ? ? ? ? ? ? [? OK? ]
?開始測試
ping?自己測試
[root@CentOS?~]#?ping?192.168.66.2
PING?192.168.66.2?(192.168.66.2)?56(84)?bytes?of?data.
64?bytes?from?192.168.66.2:?icmp_seq=1?ttl=64?
time
=0.042?ms
?
?ping網關測試
[root@CentOS?~]#?ping?192.168.66.1
PING?192.168.66.1?(192.168.66.1)?56(84)?bytes?of?data.
64?bytes?from?192.168.66.1:?icmp_seq=1?ttl=64?
time
=0.261?ms
?
?ping?nat出口測試
[root@CentOS?~]#?ping?172.16.20.183
PING?172.16.20.183?(172.16.20.183)?56(84)?bytes?of?data.
64?bytes?from?172.16.20.183:?icmp_seq=1?ttl=64?
time
=0.280?ms
?
?ping?nat外的工作機
[root@CentOS?~]#?ping?172.16.20.245
PING?172.16.20.245?(172.16.20.245)?56(84)?bytes?of?data.
64?bytes?from?172.16.20.245:?icmp_seq=1?ttl=63?
time
=2.39?ms
?
?ping?百度DNS
[root@CentOS?~]#?ping?180.76.76.76
PING?180.76.76.76?(180.76.76.76)?56(84)?bytes?of?data.
64?bytes?from?180.76.76.76:?icmp_seq=1?ttl=52?
time
=10.2
?
??
?ping?網易163
[root@CentOS?~]#?ping?www.163.com
PING?1stcncloud163.xdwscache.ourwebpic.com?(114.80.143.193)?56(84)?bytes?of?data.
64?bytes?from?114.80.143.193:?icmp_seq=1?ttl=55?
time
=9.58?ms
?
?ping?淘寶網
[root@CentOS?~]#?ping?www.taobao.com
PING?www.taobao.com.danuoyi.tbcache.com?(114.80.174.46)?56(84)?bytes?of?data.
64?bytes?from?114.80.174.46:?icmp_seq=1?ttl=48?
time
=8.83?ms
完
?
?
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