如何建立一個小型的私有網路, 然後透過你建立的 Router 當作它的 gateway 連到外面去

如何建立一個小型的私有網路, 然後透過你建立的 Router 當作它的 gateway 連到外面去

Jing, mqjing@gmail.com

Googledoc

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Points

• 希望內部私有網路上的電腦, 可以透過一台 router, 當作 gateway 連到外面 Internet
• 建立 Linux Router 當作內部網路的 Gateway, 進行 兩個網路的封包交換
• 這個 Router 是一個 run 在你機器上的簡單 VM

Procedure

Router 的設定

Step 1:  Router setup for enabling the IP forward function

Ubuntu

Configuration File [Linux Router]# /etc/sysctl.conf     net.ipv4.ip_forward=1 Command (setup will lost when system reboot) [Linux Router]# sudo sysctl -w net.ipv4.ip_forward=1 [Linux Router]# /etc/init.d/networking restart

Step 2: NAT setup (for Lab computer to access Internet)

# Route all packages from 192.168.6.0/24 to the nic of the other site (the other network) (eth0)

# Here, we go to Internet via eth0.

# Setup NAT Rule

. ./nat.sh

nat.sh

sudo iptables -t nat -A POSTROUTING -s 192.168.6.0/24 -o eth0 -j MASQUERADE

Verification

Lab PC in private network

Key Idea: Gateway => 192.168.6.254   ( Point to your new VM router running on your host) Linux (reboot will loss the setting) Step 1: boot up another vm Step 2: setup the ip to 102.168.6.x Step 3: setup default gateway to 192.168.6.254 Command:    sudo route add default gw 192.168.6.254 Step 4: check (Check if the VM can reach google DNS server)    ping 8.8.8.8

Appendix