SSH to a device on a 4G or LTE router

A mobile link gives you no public IP and charges for every megabyte. The device has to dial out, and it has to stay quiet while it waits.

Why you cannot dial in

Mobile carriers put most SIMs behind carrier-grade NAT. No router setting opens a port. See SSH behind CGNAT.

Measured on a slow link

We shape a link to 128 kbit/s, 150 ms each way and 1% packet loss, and measure:

• Idle: about 4.59 MB per device per 30 days, headers included. Extrapolated from measured pings and about 30 reconnects a month. A flaky link that redials more uses more.
• Reconnect: 49 KB at worst, of 10 runs.
• First shell: 95% of 20 opened within 11.3 s with the CLI and 8.3 s in the browser.
• Typing: 95% of keys echo within 1.5 s with the CLI and 1.7 s in the browser.

A simulated link, not a real carrier. Measured on 17 October 2026.

When signal drops

The agent retries every 60 seconds, five times, then waits 30 minutes and starts over. A device that comes back shows up again by itself.

Traffic and fair use

• Idle traffic is not counted.
• Shell traffic: 50 MB per device per month, shared across the devices on your team. Above it we slow each session to 16 KB/s. We never cut it.

€0.10 a device a month, billed yearly, at least €6 a year. Also see what to ask a customer's IT team.