Networking issue on some VM's but not others?

[jnewing]

So I recently grabbed ProxMox so I could spin up some VM's from vulnhub so I can keep working on my pentesting. Now I'm having this weird issue. The first ova I grabbed was called y0usef can be found here: https://www.vulnhub.com/entry/y0usef-1,624/ and I was able to get this working no problem.

Next one I grabbed was crossroads https://www.vulnhub.com/entry/crossroads-1,659/ and while the import process went fine it has no network?! It never even tries to get an IP from my DCHP server. Unlike the ubuntu one?

I'm not sure what to do really? Why is networking working fine in the Ubuntu based vm's but not the Debian ones? are those vm's missing a driver or something? Is there a way I can add it?

Here is my interfaces

root@home:/etc# cat /etc/network/interfaces
auto lo
iface lo inet loopback

iface enp2s0 inet manual

auto vmbr0
iface vmbr0 inet static
        address 192.168.1.15/24
        gateway 192.168.1.1
        bridge_ports enp2s0
        bridge_stp off
        bridge_fd 0

'ip a' output from working Ubuntu vm

'ip a' output from non-working Debian

Update

So after some more digging it seem that all the debian vm's don't use the correct interface in the /etc/network/interfaces file... I have no idea why or when / where these get set. But if you look at the screen shot below, they are all trying to use the "enp0s3" device (which is a valid ethernet device on the actual proxmox server itself but not the VM. The interface should be trying to use "ens18" if we look at the output from ip a on the Debian systems.

Is there a way I can correct this, other than manually for each Debian VM?


Thanks for reading.

 

[Moayad]

Hello,

Have you set a static name for the network interface in your host? what say the output of pveversion -v and config for the Debian VM qm config <VMID>

Is there a way I can correct this, other than manually for each Debian VM?

Since Debian Stretch (9), new installations abandoned the old naming scheme (eth0, ensX ...) but if the `70-local-persistent-net.rules` udev rule file is present on systems that have been installed before that, they should still be honored [0]



[0] https://wiki.debian.org/NetworkConfiguration#Network_Interface_Names

 

[jnewing]

Hello,

Have you set a static name for the network interface in your host? what say the output of pveversion -v and config for the Debian VM qm config <VMID>



Since Debian Stretch (9), new installations abandoned the old naming scheme (eth0, ensX ...) but if the `70-local-persistent-net.rules` udev rule file is present on systems that have been installed before that, they should still be honored [0]



[0] https://wiki.debian.org/NetworkConfiguration#Network_Interface_Names

Here is the output requsted.

root@home:~# pveversion -v
proxmox-ve: 6.3-1 (running kernel: 5.4.73-1-pve)
pve-manager: 6.3-2 (running version: 6.3-2/22f57405)
pve-kernel-5.4: 6.3-1
pve-kernel-helper: 6.3-1
pve-kernel-5.4.73-1-pve: 5.4.73-1
ceph-fuse: 12.2.11+dfsg1-2.1+b1
corosync: 3.0.4-pve1
criu: 3.11-3
glusterfs-client: 5.5-3
ifupdown: 0.8.35+pve1
ksm-control-daemon: 1.3-1
libjs-extjs: 6.0.1-10
libknet1: 1.16-pve1
libproxmox-acme-perl: 1.0.5
libproxmox-backup-qemu0: 1.0.2-1
libpve-access-control: 6.1-3
libpve-apiclient-perl: 3.0-3
libpve-common-perl: 6.2-6
libpve-guest-common-perl: 3.1-3
libpve-http-server-perl: 3.0-6
libpve-storage-perl: 6.3-1
libqb0: 1.0.5-1
libspice-server1: 0.14.2-4~pve6+1
lvm2: 2.03.02-pve4
lxc-pve: 4.0.3-1
lxcfs: 4.0.3-pve3
novnc-pve: 1.1.0-1
proxmox-backup-client: 1.0.5-1
proxmox-mini-journalreader: 1.1-1
proxmox-widget-toolkit: 2.4-3
pve-cluster: 6.2-1
pve-container: 3.3-1
pve-docs: 6.3-1
pve-edk2-firmware: 2.20200531-1
pve-firewall: 4.1-3
pve-firmware: 3.1-3
pve-ha-manager: 3.1-1
pve-i18n: 2.2-2
pve-qemu-kvm: 5.1.0-7
pve-xtermjs: 4.7.0-3
qemu-server: 6.3-1
smartmontools: 7.1-pve2
spiceterm: 3.1-1
vncterm: 1.6-2
zfsutils-linux: 0.8.5-pve1

root@home:~# qm config 101
boot: order=scsi0
cores: 2
ide2: none,media=cdrom
memory: 2048
name: crossroads
net0: virtio=56:98:69:A6:49:81,bridge=vmbr0
numa: 0
ostype: l26
scsi0: local-lvm:vm-101-disk-0,size=8G
scsihw: virtio-scsi-pci
smbios1: uuid=f0fdb8a7-c608-4f40-b027-eddb539300e8
sockets: 1
vmgenid: 6615229e-13c3-4ba5-aca4-9926c1b6c4bb

 

[kcrawford]

Did you ever come up with a solution to this problem? I am facing the same issue when attempting to run ova files downloaded from vulnhub.

 

[Moayad]

The fix is only by editing the network interface name in the network configuration, then rebooting the VM.

 

[kcrawford]

The fix is only by editing the network interface name in the network configuration, then rebooting the VM.

This is what I believe will need to be done. For future fourm-goers finding this post through Google, changing the grub menu to boot into single user mode and editing /etc/network/interfaces file to set dhcp is likely the easiest path forward.