Retrieving VM IP Addresses in KVM with virsh

When you create VMs in KVM, they’re typically assigned IP addresses via DHCP. Finding those addresses so you can SSH in requires a few steps. Here are the practical approaches.

Using virsh domiflist and ARP

The traditional method combines virsh domiflist to get the VM’s MAC address, then looks it up in the ARP table:

$ virsh domiflist hvm1
 Interface  Type       Source     Model       MAC
 -------------------------------------------------------
 vnet0      network    default    virtio      52:54:00:1c:36:cd

Note the MAC address (52:54:00:1c:36:cd). Then check the ARP table:

$ arp -e
Address                  HWtype  HWaddress           Flags Mask            Iface
10.80.1.17               ether   52:54:00:2b:08:c3   C                     br0
10.80.1.16               ether   52:54:00:78:02:89   C                     br0
192.168.122.210          ether   52:54:00:1c:36:cd   C                     virbr0

Match the MAC from domiflist with the ARP entry. In this case, hvm1 has IP 192.168.122.210.

Using virsh domifaddr (Better Approach)

Modern versions of libvirt (0.10.0+) provide a more direct method with virsh domifaddr:

$ virsh domifaddr hvm1
 Name       MAC address          IPv4 Address     IPv6 Address
 ---------------------------------------------------------------
 vnet0      52:54:00:1c:36:cd    192.168.122.210  --

This works only if the guest has QEMU Guest Agent installed and running, or if libvirt can query the VM’s network configuration directly. This is the preferred approach as it eliminates the need to cross-reference ARP tables.

Using ip Command (With QEMU Guest Agent)

If your guest has the QEMU Guest Agent (qemu-guest-agent package) installed, you can also use:

$ virsh qemu-agent-command hvm1 '{"execute":"guest-network-get-interfaces"}'

This directly queries the guest’s network interfaces. Install the agent in the guest:

# Debian/Ubuntu
sudo apt-get install qemu-guest-agent

# RHEL/CentOS/Fedora
sudo yum install qemu-guest-agent

# Then restart the guest agent service
sudo systemctl restart qemu-guest-agent

Scripting Multiple VMs

To get IP addresses for all running VMs:

#!/bin/bash
for vm in $(virsh list --name); do
    echo "VM: $vm"
    virsh domifaddr "$vm" 2>/dev/null || {
        # Fallback to ARP method
        mac=$(virsh domiflist "$vm" | awk 'NR>2 {print $NF}' | grep -oE '([0-9a-f]{2}:){5}[0-9a-f]{2}')
        arp -e | grep -i "$mac" | awk '{print $1}'
    }
done

Troubleshooting

domifaddr returns nothing: The guest doesn’t have the QEMU Guest Agent running. Either install it or rely on ARP lookups. Note that some guests behind complex networking setups may not appear in local ARP tables if they’re on different network segments.

ARP entry not appearing: The VM hasn’t sent any ARP requests yet. SSH or ping into the VM’s network from another host to trigger an ARP entry. Alternatively, run arp-scan or nmap on your network range:

sudo arp-scan -l
sudo nmap -sn 192.168.122.0/24

IP keeps changing: Configure static IP addresses in the guest or use DHCP reservations in your libvirt network definition to assign consistent IPs based on MAC address.

Persistent DHCP Reservations

Edit your libvirt network to reserve IPs by MAC:

$ virsh net-edit default

Add this inside the <network> block:

<dhcp>
  <range start='192.168.122.2' end='192.168.122.254' />
  <host mac='52:54:00:1c:36:cd' name='hvm1' ip='192.168.122.100' />
</dhcp>

Then restart the network:

$ virsh net-destroy default
$ virsh net-start default

The virsh domifaddr approach is the cleanest for modern setups, but understanding the ARP method provides a fallback when guest tools aren’t available.