Re: Network bridge and MAC address exposure
On Sun, 4 Sep 2022 08:39:59 +0200 Rand Pritelrohm wrote: >Hello, > >I am not a network specialist and despite a lot of documentation >readings and searchs on the net I haven't get a simple and clear answer >to my question. > [...] > > >Here is my question: >For both scenarios, what is the effectively seen MAC address by the >GW when the VM access the Internet (host or VM MAC address)? Hello, Thank you all for contribution. I will investigate further with wireshark. Regards, -- Rand Pritelrohm
Network bridge and MAC address exposure
Hello, I am not a network specialist and despite a lot of documentation readings and searchs on the net I haven't get a simple and clear answer to my question. Consider this simple schematic: | VM | -> | HOST | -> | GW | -> ISP Lets say the physical interface name on the 'host' is eth0 and the LAN subnet is 192.168.0.0. I want to configure the network on the 'host' in order for the VM to access the Internet. Thus I consider 2 scenarios to setup the 'host' network. 1. Bridge using routed subnet: ip link add dev br0 type bridge ip addr add 192.168.222.1/24 dev br0 ip link set dev br0 up ip tuntap add tap0 mode tap ip link set dev tap0 up ip link set dev tap0 master br0 #Then I have to enable routing echo '1' > /proc/sys/net/ipv4/ip_forward iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE 2. Bridge on the same subnet as the LAN: ip link add dev br0 type bridge ip link set dev br0 up ip link set dev eth0 master br0 ip link set dev eth0 up ip addr add 192.168.0.200/24 dev br0 ip route add default via 192.168.0.1 ip tuntap add tap0 mode tap ip link set dev tap0 up ip link set dev tap0 master br0 For both scenarios the VM is then setup with it's own MAC address and it's IP on the configured subnet of the bridge. Here is my question: For both scenarios, what is the effectively seen MAC address by the GW when the VM access the Internet (host or VM MAC address)? Regards, Rand.
