Networking Modes

vmctl supports several networking modes depending on your needs and permissions.

User Mode (SLIRP) - Default

network "user"

QEMU's built-in user-mode networking. No root or special permissions required.

How it works:

• QEMU emulates a full TCP/IP stack in userspace.
• The guest gets a private IP (typically 10.0.2.x).
• Outbound connections from the guest are NAT'd through the host.
• SSH access is provided via host port forwarding (ports 10022-10122, deterministically assigned per VM name).

Pros: Zero setup, no root needed. Cons: No inbound connections (except forwarded ports), lower performance than TAP.

TAP Mode

network "tap" {
    bridge "br0"
}

Creates a TAP device and attaches it to a host bridge. The guest appears as a real machine on the bridge's network.

How it works:

• vmctl creates a TAP interface and bridges it.
• The guest gets an IP via DHCP from whatever serves the bridge network.
• Full Layer 2 connectivity.

Pros: Real network presence, full inbound/outbound, better performance. Cons: Requires bridge setup, may need root or appropriate capabilities.

If no bridge name is specified, it defaults to br0.

VNIC Mode (illumos only)

network "vnic" {
    name "vnic0"
}

Uses an illumos VNIC for exclusive-IP zone networking. Only available on the Propolis backend.

None

network "none"

No networking at all. Useful for isolated compute tasks or testing.

IP Discovery

vmctl discovers the guest IP differently depending on the network mode: