Part 2. Linux bridge (Virtual bridge)

Before

ifconfig
eth0      Link encap:Ethernet  HWaddr 08:00:27:7a:94:3d 
          inet addr:192.168.0.36  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe7a:943d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:288 errors:0 dropped:0 overruns:0 frame:0
          TX packets:273 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:61152 (61.1 KB)  TX bytes:35117 (35.1 KB)
lo        Link encap:Local Loopback 
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:4 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:240 (240.0 B)  TX bytes:240 (240.0 B)
 
vdkmai@Ubuntu32bit:~$ brctl
The program 'brctl' is currently not installed. You can install it by typing:
sudo apt-get install bridge-utils

Setup

sudo apt-get install bridge-utils

Usage

Usage: brctl [commands]
commands:
        addbr                           add bridge
        delbr                           delete bridge
        addif                   add interface to bridge
        delif                   delete interface from bridge
        hairpin           {on|off}        turn hairpin on/off
        setageing                 set ageing time
        setbridgeprio             set bridge priority
        setfd                     set bridge forward delay
        sethello                  set hello time
        setmaxage                 set max message age
        setpathcost         set path cost
        setportprio         set port priority
        show            [  ]            show a list of bridges
        showmacs                        show a list of mac addrs
        showstp                         show bridge stp info
        stp              {on|off}       turn stp on/off

Usage: brctl [commands] commands:         addbr           <bridge>                add bridge         delbr           <bridge>                delete bridge         addif           <bridge> <device>       add interface to bridge         delif           <bridge> <device>       delete interface from bridge         hairpin         <bridge> <port> {on|off}        turn hairpin on/off         setageing       <bridge> <time>         set ageing time         setbridgeprio   <bridge> <prio>         set bridge priority         setfd           <bridge> <time>         set bridge forward delay         sethello        <bridge> <time>         set hello time         setmaxage       <bridge> <time>         set max message age         setpathcost     <bridge> <port> <cost>  set path cost         setportprio     <bridge> <port> <prio>  set port priority         show            [ <bridge> ]            show a list of bridges         showmacs        <bridge>                show a list of mac addrs         showstp         <bridge>                show bridge stp info         stp             <bridge> {on|off}       turn stp on/off

vdkmai@Ubuntu32bit:~$ sudo brctl addbr vCisco

vdkmai@Ubuntu32bit:~$ brctl show
bridge name bridge id STP enabled interfaces
vCisco 8000.000000000000 no

vdkmai@Ubuntu32bit:~$ sudo ip link add type veth vdkmai@Ubuntu32bit:~$ vdkmai@Ubuntu32bit:~$ vdkmai@Ubuntu32bit:~$ ifconfig eth0      Link encap:Ethernet  HWaddr 08:00:27:7a:94:3d            inet addr:192.168.0.36  Bcast:192.168.0.255  Mask:255.255.255.0           inet6 addr: fe80::a00:27ff:fe7a:943d/64 Scope:Link           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:525 errors:0 dropped:0 overruns:0 frame:0           TX packets:388 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000           RX bytes:82986 (82.9 KB)  TX bytes:48549 (48.5 KB) lo        Link encap:Local Loopback            inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:65536  Metric:1           RX packets:4 errors:0 dropped:0 overruns:0 frame:0           TX packets:4 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:0           RX bytes:240 (240.0 B)  TX bytes:240 (240.0 B) vdkmai@Ubuntu32bit:~$ ifconfig -a eth0      Link encap:Ethernet  HWaddr 08:00:27:7a:94:3d            inet addr:192.168.0.36  Bcast:192.168.0.255  Mask:255.255.255.0           inet6 addr: fe80::a00:27ff:fe7a:943d/64 Scope:Link           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:535 errors:0 dropped:0 overruns:0 frame:0           TX packets:393 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000           RX bytes:83816 (83.8 KB)  TX bytes:49991 (49.9 KB) lo        Link encap:Local Loopback            inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:65536  Metric:1           RX packets:4 errors:0 dropped:0 overruns:0 frame:0           TX packets:4 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:0           RX bytes:240 (240.0 B)  TX bytes:240 (240.0 B) vCisco    Link encap:Ethernet  HWaddr 8e:fb:13:53:d2:7a            BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:0           RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B) veth0     Link encap:Ethernet  HWaddr 16:74:bc:b4:c4:16            BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000           RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B) veth1     Link encap:Ethernet  HWaddr 9a:49:33:f6:6e:79            BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000           RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

sudo ifconfig veth0 10.0.0.10 netmask 255.255.255.0 up sudo ifconfig veth2 10.0.0.12 netmask 255.255.255.0 up sudo brctl addif vCisco veth1 sudo brctl addif vCisco veth3 vdkmai@Ubuntu32bit:~$ brctl show vCisco bridge name     bridge id               STP enabled     interfaces vCisco          8000.0ee3838584ff       no              veth1                                                         veth3

Example to create veth interfaces with custom names: lnsgmii0 & nsgmii0. You can use any name which you want.

sudo ip link add lnsgmii0 type veth peer name nsgmii0 ifconfig -a eth0      Link encap:Ethernet  HWaddr 08:00:27:7a:94:3d            inet addr:192.168.0.36  Bcast:192.168.0.255  Mask:255.255.255.0           inet6 addr: fe80::a00:27ff:fe7a:943d/64 Scope:Link           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:1330 errors:0 dropped:0 overruns:0 frame:0           TX packets:612 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000           RX bytes:116571 (116.5 KB)  TX bytes:79276 (79.2 KB) lnsgmii0  Link encap:Ethernet  HWaddr 96:8f:8c:ca:bb:49            BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000           RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B) nsgmii0   Link encap:Ethernet  HWaddr 9e:ed:69:fa:93:b1            BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000           RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

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