TIL: How to Access a DGX Spark Headlessly Over Ethernet (No Wi-Fi, No Router)

TIL that the most reliable way to access a DGX Spark while traveling is direct Ethernet with a static IP, completely independent of hotel Wi-Fi, routers, or DHCP.

This setup lets me SSH into the DGX from my laptop anywhere—hotel rooms, conference venues, even offline—using just an Ethernet cable.

The Problem

Hotel Wi-Fi is unreliable (captive portals, VLAN isolation, firewalls)
DHCP IPs can change
NVIDIA Sync discovery can fail across networks
I don’t carry a monitor or keyboard

I needed deterministic, headless access.

The Solution: Direct Ethernet (Point-to-Point)

Use a static, private IP on both the DGX and the laptop, connected by a single Ethernet cable.

No router. No DHCP. No Wi-Fi.

One-Time Setup on DGX Spark

Identify the Ethernet interface (mine is enP7s7) and create a dedicated static profile:

sudo nmcli connection add \
  type ethernet \
  ifname enP7s7 \
  con-name direct-ethernet \
  ipv4.method manual \
  ipv4.addresses 10.10.10.2/24 \
  ipv6.method ignore \
  autoconnect yes

Activate it:

sudo nmcli connection up direct-ethernet

Verify:

ip -4 addr show enP7s7
# Expect: 10.10.10.2/24

(Optional but recommended)

sudo nmcli radio wifi off

Laptop Setup (Static IP)

Set your laptop’s Ethernet interface to:

IP: 10.10.10.1
Subnet: 255.255.255.0
Gateway: (leave blank)

This is a pure point-to-point link—no routing needed.

How I Use It While Traveling

Plug Ethernet cable directly: Laptop ↔ DGX Spark
Wait ~5 seconds for link-up
SSH:

ssh sameersegal@10.10.10.2

That’s it.

No Wi-Fi. No internet. No surprises.

Why This Works So Well

Deterministic and repeatable
Immune to hotel networks and captive portals
Survives reboots
No dependency on NVIDIA Sync (SSH is primary)
Works anywhere electricity exists

This is exactly how servers are brought up in data centers—and it works just as well on the road.

Pre-Travel Checklist

Test direct Ethernet now
Reboot DGX and re-test
Confirm SSH + nvidia-smi
Pack Ethernet cable

Takeaway

TIL: For headless systems, direct Ethernet with static IPs beats every “smart” networking option. Simple, boring, and rock-solid—which is exactly what you want when you’re traveling.

Sustaining high effort ⇢
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