Jan 4, 2017

7. Demo: VLANs inside a Linux machine with Internet access

By Phèn January 04, 2017 Leave a Comment

Topology


Expected result
  • All PCs can access Internet
  • All can see each other (directly if in the same VLAN or via host interface if in different VLANs)

Configuration

#Create namespaces and virtual switch
sudo ip netns add pc1
sudo ip netns add pc2
sudo ip netns add pc3
sudo ip netns add pc4
sudo brctl addbr vSwitch
 
#Create vEth interface pairs
sudo ip link add eth1 type veth peer name eth5
sudo ip link add eth2 type veth peer name eth6
sudo ip link add eth3 type veth peer name eth7
sudo ip link add eth4 type veth peer name eth8
  
#Add interfaces to namespaces
sudo ip link set eth1 netns pc1
sudo ip link set eth2 netns pc2
sudo ip link set eth3 netns pc3
sudo ip link set eth4 netns pc4
 
#Add interfaces to switch
sudo brctl addif vSwitch eth5
sudo brctl addif vSwitch eth6
sudo brctl addif vSwitch eth7
sudo brctl addif vSwitch eth8
 
 
#Create vlan interface on namespaces
sudo ip netns exec pc1 ip link add link eth1 name vlan type vlan id 10
sudo ip netns exec pc2 ip link add link eth2 name vlan type vlan id 10
sudo ip netns exec pc3 ip link add link eth3 name vlan type vlan id 20
sudo ip netns exec pc4 ip link add link eth4 name vlan type vlan id 20
  
#Set IP address
sudo ip netns exec pc1 ip addr add 10.0.0.1/25 dev vlan
sudo ip netns exec pc2 ip addr add 10.0.0.2/25 dev vlan
sudo ip netns exec pc3 ip addr add 10.0.0.203/25 dev vlan
sudo ip netns exec pc4 ip addr add 10.0.0.204/25 dev vlan
 
 
#Turn on interfaces
sudo ip netns exec pc1 ip link set eth1 up
sudo ip netns exec pc2 ip link set eth2 up
sudo ip netns exec pc3 ip link set eth3 up
sudo ip netns exec pc4 ip link set eth4 up
sudo ip link set vSwitch up
sudo ip link set eth5 up
sudo ip link set eth6 up
sudo ip link set eth7 up
sudo ip link set eth8 up
sudo ip netns exec pc1 ip link set vlan up
sudo ip netns exec pc2 ip link set vlan up
sudo ip netns exec pc3 ip link set vlan up
sudo ip netns exec pc4 ip link set vlan up
  
#Create vlan interface on Host machine and set IP address
sudo ip link add link vSwitch name vlan10 type vlan id 10
sudo ip link add link vSwitch name vlan20 type vlan id 20
sudo ip addr add 10.0.0.10/25 dev vlan10
sudo ip addr add 10.0.0.220/25 dev vlan20
sudo ip link set vlan10 up
sudo ip link set vlan20 up
 
#Set default gateway for namespaces
sudo ip netns exec pc1 route add default gw 10.0.0.10 vlan
sudo ip netns exec pc2 route add default gw 10.0.0.10 vlan
sudo ip netns exec pc3 route add default gw 10.0.0.220 vlan
sudo ip netns exec pc4 route add default gw 10.0.0.220 vlan
 
#Set forwarding route for host machine
sudo bash -c 'echo 1 > /proc/sys/net/ipv4/ip_forward'
sudo iptables -t nat -A POSTROUTING -o eth0 -j  MASQUERADE
 
#Check result
sudo ip netns exec pc1 ping 8.8.8.8
sudo ip netns exec pc2 ping 8.8.8.8
sudo ip netns exec pc3 ping 8.8.8.8
sudo ip netns exec pc4 ping 8.8.8.8

Result

vdkmai@Ubuntu32bit:~$ sudo ip netns exec pc1 ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_req=1 ttl=52 time=38.6 ms
^C
--- 8.8.8.8 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 38.612/38.612/38.612/0.000 ms
vdkmai@Ubuntu32bit:~$ sudo ip netns exec pc2 ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_req=1 ttl=52 time=32.7 ms
^C
--- 8.8.8.8 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 32.771/32.771/32.771/0.000 ms
vdkmai@Ubuntu32bit:~$ sudo ip netns exec pc3 ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_req=1 ttl=52 time=32.9 ms
^C
--- 8.8.8.8 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 32.986/32.986/32.986/0.000 ms
vdkmai@Ubuntu32bit:~$ sudo ip netns exec pc4 ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_req=1 ttl=52 time=31.0 ms
^C
--- 8.8.8.8 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 31.066/31.066/31.066/0.000 ms
vdkmai@Ubuntu32bit:~$ sudo ip netns exec pc1 ping 10.0.0.203
PING 10.0.0.203 (10.0.0.203) 56(84) bytes of data.
64 bytes from 10.0.0.203: icmp_req=1 ttl=63 time=0.088 ms
^C
--- 10.0.0.203 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.088/0.088/0.088/0.000 ms
vdkmai@Ubuntu32bit:~$ sudo ip netns exec pc1 ping 10.0.0.2
PING 10.0.0.2 (10.0.0.2) 56(84) bytes of data.
64 bytes from 10.0.0.2: icmp_req=1 ttl=64 time=0.450 ms
^C
--- 10.0.0.2 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.450/0.450/0.450/0.000 ms
vdkmai@Ubuntu32bit:~$ sudo ip netns exec pc1 traceroute 10.0.0.2
traceroute to 10.0.0.2 (10.0.0.2), 30 hops max, 60 byte packets
 1  10.0.0.2 (10.0.0.2)  0.048 ms  0.007 ms  0.008 ms
vdkmai@Ubuntu32bit:~$ sudo ip netns exec pc1 traceroute 10.0.0.203
traceroute to 10.0.0.203 (10.0.0.203), 30 hops max, 60 byte packets
 1  10.0.0.10 (10.0.0.10)  0.047 ms  0.009 ms  0.007 ms
 2  10.0.0.203 (10.0.0.203)  0.030 ms  0.015 ms  0.012 ms
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