howdy,
I had to start using a dummy interface in bring mobility to my lab. It’s a demo in-a-box. Every time that I’ve tried to disconnect it and use other network. I had to make a lot of changes to my configuration: it’s messy.
Create your permanent dummy interface
I had to make the following change to my box:
[root@box01 ~]# cat /etc/modprobe.d/dummy.conf install dummy /sbin/modprobe --ignore-install dummy; /sbin/ip link set name ethdummy1 dev dummy0 [root@box01 ~]# cat /etc/modules-load.d/dummy.conf # Load dummy.ko at boot dummy [root@box01 ~]# cat /etc/sysconfig/network-scripts/ifcfg-ethdummy1 NAME=ethdummy1 DEVICE=ethdummy1 MACADDR=00:22:22:ff:ff:ff IPADDR=10.10.10.1 NETMASK=255.255.255.0 ONBOOT=yes TYPE=Ethernet NM_CONTROLLED=no
After reboot, check if you dummy is there:
[root@box01 ~]# ifconfig ethdummy1 ethdummy1: flags=195<UP,BROADCAST,RUNNING,NOARP> mtu 1500 inet 10.10.10.1 netmask 255.255.255.0 broadcast 10.10.10.255 ether 00:22:22:ff:ff:ff txqueuelen 0 (Ethernet)
Got i from this forum thread: Permanent dummy interface
turn your dummy into a bridge
I’ll bridge ethdummy to bridge0:
[root@box01 ~]# cat /etc/sysconfig/network-scripts/ifcfg-ethdummy1 NAME=ethdummy1 DEVICE=ethdummy1 #MACADDR=00:22:22:ff:ff:ff #IPADDR=10.10.10.1 #NETMASK=255.255.255.0 ONBOOT=yes #TYPE=Ethernet NM_CONTROLLED=no BRIDGE=bridge0 [root@box01 ~]# cat /etc/sysconfig/network-scripts/ifcfg-bridge0 DEVICE="bridge0" ONBOOT="yes" TYPE=Bridge BOOTPROTO=static IPADDR=10.10.10.1 NETMASK=255.255.255.0
Restart network services: service network restart
And let’s check this out.
[root@box01 ~]# brctl show bridge name bridge id STP enabled interfaces bridge0 8000.002222ffffff no ethdummy1
Important Notes
Don’t forget to use iptables to translate IPs and get Internet access from your VMs connected to this new bridge (servers need to use dummy interface as the default gateway: 10.10.10.1)
# You need to translate your IPs thru eth0 # eth0 is the interface connected to the Network iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
That’s all
See ya!
One thought on “Bridge your dummy interface in centos7”