Use DuoBook away from home

With Access from anywhere on, DuoBook Host asks your router to let your iPhone in from the internet. Routers do this with a setting called UPnP (sometimes “Universal Plug and Play”) or NAT-PMP. If DuoBook Host says “Your router didn’t allow it”, that setting is off. Turn it on once and you’re done.

Turn it on

On your Mac, open DuoBook Host from the menu bar, then Settings, and click Open Router Settings. Your router’s page opens in your browser. (Or type its address yourself: often 192.168.1.1, 192.168.0.1 or 10.0.0.1.) Some routers are set up in their own app instead; see the list below.
Sign in. The password is usually on a sticker on the router, unless you changed it.
Find UPnP or NAT-PMP, turn it on, and click Save (or Apply). Selecting Enable isn’t enough on most routers: nothing changes until you save. Where it lives for common routers is below. Leave the other settings on that page as they are.
Back in DuoBook Host, turn Access from anywhere off and on again. It should now say your router forwards DuoBook. If it still says your router didn’t allow it, quit DuoBook Host and open it again (it also tries again by itself every two minutes).
Connect from your iPhone once at home, on your Wi-Fi. That’s when your iPhone learns how to reach your Mac from outside. After that it connects from anywhere.

Check that it works

On your iPhone, turn Wi-Fi off in the Settings app. Not in Control Center: that only disconnects from your network, and your iPhone can still reach a Mac in the same room directly, so the test would pass without the internet.
Open DuoBook and tap your Mac under Your Macs. (Don’t tap Pair: pairing only works at home, on the same Wi-Fi as the Mac.)
It connects over the internet. To see it, turn on DuoBook → Settings → Show connection speed: DuoBook shows “Internet” next to the speed instead of “Wi-Fi”. DuoBook Host’s menu says Over the internet.

Away from home, Automatic quality uses a lighter picture to save cellular data. For a sharper one, set Quality to High in DuoBook’s Settings (or its ⋯ menu while connected).

Where to find it

Menus change between models and updates, so these are the usual places. If yours looks different, search the web for your router’s model and “UPnP”.

Apple AirPort

NAT-PMP is on by default. To check: AirPort Utility → select your base station → Edit → Network → Enable NAT Port Mapping Protocol.

eero

In the eero app: Settings → Network settings → Advanced settings → UPnP.

Google Nest Wifi and Google Wifi

In the Google Home app: Wi-Fi → Settings → Advanced networking → UPnP.

NETGEAR (Nighthawk, Orbi)

Go to routerlogin.net (Orbi: orbilogin.com) → Advanced → Advanced Setup → UPnP → Turn UPnP On → Apply.

TP-Link (Archer, Deco)

Archer: go to tplinkwifi.net → Advanced → NAT Forwarding → UPnP. Deco: in the Deco app, More → Advanced → UPnP.

ASUS

Go to router.asus.com → WAN → Internet Connection → Enable UPnP: Yes → Apply.

Linksys

Go to myrouter.local (or the Linksys app) → Connectivity → Administration → UPnP.

FRITZ!Box

Go to fritz.box → Internet → Permit Access → Port Sharing → edit your Mac → turn on Permit independent port sharing for this device.

Xfinity, Rogers Ignite, Vidéotron Helix, Shaw

These gateways share the same setup page. Go to 10.0.0.1 and sign in → Advanced → Device Discovery → UPnP: Enable → Save. Leave Advertisement Period, Time To Live and Zero Config as they are: DuoBook doesn’t need them. (Tested on a Vidéotron Helix Fi.)

Bell Home Hub

Go to 192.168.2.1 → Advanced tools and settings → UPnP.

Still not working?

You have two routers (your provider’s box plus your own)

Then there are two routers in the way. Turn on UPnP on both, or set your provider’s box to bridge mode so only your own router is in charge. Your provider can help with bridge mode.

Starlink, 5G home internet, or a shared address (CGNAT)

Some providers share one internet address between many homes. Starlink and most 5G home internet plans (T-Mobile, Verizon and others) work this way, and some cable and fiber providers do too. Then no router setting can let DuoBook in. Ask your provider for a public IP address, or use a free VPN such as Tailscale on both your Mac and iPhone and type your Mac’s Tailscale address in DuoBook → Settings → Your Macs → your Mac → Direct address.

There’s no UPnP or NAT-PMP setting

Some office and building networks don’t offer it. Use the VPN option above instead.

Is it safe?

Only iPhones you paired can connect, and pairing only works on your own Wi-Fi with a code shown on both screens. Every connection is encrypted end to end. UPnP lets apps on your home network ask the router to open a door for themselves, so turn it on only if you trust the devices on your network. You can turn it off again any time.

Questions? Write to info@mehdichitsaz.com with your router’s brand and model.