Ports Closed in Hub 4 Modem Mode

[seanelvidge]

Hi all,

I have a Hub 4 set up in Modem Mode with a Nest (Google) WiFi mesh router. 

I am having trouble with port forwarding - everything is seemingly set up correctly on my Nest router (as confirmed by Google Support) but it doesn't work and an online port scanner shows it as closed (testing on port 22).

The latest round of Google Support suggest that the "ports are closed within your ISP connection". As far as I can tell in modem Mode there is no firewall (or similar) which needs configuring to allow this to work? 

Any hints? Am I doing something wrong with the router in Modem Mode? Should I do something to enable port forwarding? 

I've read every post I can find on the subject on this forum, but I just want to quadruple check before going back to the Google Support agent (who has been very helpful to be honest!)

Thanks for your support,

Sean.

[jem101]

In modem mode, the Hub isn’t doing anything other than passing the connection on to your own Google router. It doesn’t block any ports (OK there are one or two that VM do block by default but 22 isn’t one of them).

Now I assume that your port forwarding is set up properly and that port 22 is open and listening on the target device. Try it from an IP address on your internal network first.

[seanelvidge]

Hi,

Yes I read online about which ports VM block so that's not the problem, and you've confirmed that in Modem Mode it essentially does nothing (as expected).

Machine in question has got a static IP and port forwarding is set up correctly (well apart from the fact it doesn't work...). Port on the machine is open, and I can SSH into it (on 22) from an internal IP.

But using an online port scanner or nmap on my public IP just shows the port as closed.

[legacy1]

Its likely your router or firewall to device, so remove the router and connect the device or PC to the hub in modem mode with port Listener on TCP 22
http://www.rjlsoftware.com/software/utility/portlistener/

[seanelvidge]

Hi,

I agree that it is likely the router. I have tried connecting my machine directly to the hub in modem mode, but I then can't get online at all and can only connect to the modem (on 192.168.100.1) for about a minute during the boot up stage. Once the modem "settles" I can't even access the modem login page (unless it is on something other than 192.168.100.1?).

Is it possible to actually get online via a modem without a router?

Thanks

[carl_pearce]

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@seanelvidge wrote:

Hi,

I agree that it is likely the router. I have tried connecting my machine directly to the hub in modem mode, but I then can't get online at all and can only connect to the modem (on 192.168.100.1) for about a minute during the boot up stage. Once the modem "settles" I can't even access the modem login page (unless it is on something other than 192.168.100.1?).

Is it possible to actually get online via a modem without a router?

Thanks

---

Yes, the HUB provides an IP to one wired device in modem mode.

Each time a new device is connected the HUB must be rebooted as it 'latches' onto the MAC address of that specific device.

HOWEVER, if you have given your device a static IP this process won't work as the IP range will differ.

[legacy1]

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@seanelvidge wrote:

Is it possible to actually get online via a modem without a router?

---

Yes power off the hub when in modem mode for 2mins power on and wait 5mins if no internet unplug and replug the Ethernet cable till you do.. 

[seanelvidge]

Thanks (and sorry for the delay in replying).

Turns out cycling the power once more got it to work (and potentially leaving it turned off for longer?). 

Anyway, I am now connected directly connected in Modem Mode - and interestingly I still have all my ports showing as closed I tested a couple of different port scanning sites as well as using nmap all show the same. I was expecting when in Modem Mode every port to show as open?

Feels like we're iterating towards the issue - thanks for your help.

Sean.

[Kath_F]

Hi Sean, 

Thanks for your post in the Community. 

I'm glad to see the Community have managed to help get things sorted for you. Please Kudos any posts you found helpful. 

Let us know if you have any further issues going forward. 

Thanks, 

[Tudor]

“I was expecting when in Modem Mode every port to show as open?” ports are always shown as closed until there is app or code ‘listening’ on that port.