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The host machine runs a newly installed Fedora 31. Using Cockpit, I created two VM running Fedora as well. For the network configuration, I chose the "Direct attachment" type.

Now, each VM and the host can access internet no problem, and they can ping other machines on my local network. But the VM can't ping each other, can't ping the host, and the host can't ping them either.

As they all use the same physical interface eno2, I could imagine this is the source of the issue. But the VM can't ping the host even on its other IP associated with the wifi card.

Now for my questions :

  • is this behavior expected with "direct attachment"?
  • how should I configure my VMs so they can talk to each other and to all the other machines on the local network?
user123065
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    Using macvtap interfaces in private mode would, as expected, have all the symptoms you're describing. Now I don't know if "direct attachment" translates to macvtap. Does it? – A.B Apr 20 '20 at 01:34
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    You could check by having the VMs running and on the host typing `ip -d link show type macvtap`. If you get two interfaces (one per VM), that should mean it's the case (and the default is probably `mode vepa` rather than private, same effect without proper network config) – A.B Apr 20 '20 at 01:47
  • Yes, I found two interfaces as you predicted, in mode vepa. – user123065 Apr 20 '20 at 07:59
  • I can't answer this question. If the graphical interface doesn't offer access to other modes, even VM to VM will be difficult. VM to host is anyway more difficult once you know how it's actually working (emitted frames never come back, so the host never sees them). – A.B Apr 20 '20 at 13:22
  • for VM to VM it might just work by changing the mode: `ip link set intf1 type macvtap mode bridge` – A.B Apr 20 '20 at 13:23
  • some doc for macvlan and macvtap: https://developers.redhat.com/blog/2018/10/22/introduction-to-linux-interfaces-for-virtual-networking/#macvlan . If you're supposed to use VEPA, then ask your network colleague to configure the switch for hairpin. – A.B Apr 20 '20 at 13:24
  • I was hopping to have my VMs running without spending to much time reading the doc thanks to cockpit, I guess that won't happen. Thank you for your pointers A.B, I'm actually doing this at home, so there is no network colleague to help me. – user123065 Apr 20 '20 at 18:20

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