This topic

Can't access SmartHub 2 from different local subnet

jamespavett — Wed, 20 Mar 2024 00:35:31 GMT

Hello,

Not sure if what I am asking will be out of scope of this forum, and I am pretty new to networking as well, but I will give it a go.

I'm currently setting up a Unifi home network, and am currently using by Smart Hub 2 in AP mode (or as close as can be after following guides on this forum).

Currently the SmartHub 2 resides in a different subnet that the majority of my other devices. The annoying thing is I can't see to access the router (admin panel, ping, traceroute) from any subnet other than the default 192.168.x.x range.

I know on Windows pings from outside the local subnet are blocked by default, and I'm wondering if I am wasting my time and there is nothing that can be done here.

Just to confirm, I can ping/contact other devices on the same subnet as the router/AP, just not the device itself.

Any guidance would be much appreciated!

Re: Can't access SmartHub 2 from different local subnet

Crimliar — Wed, 20 Mar 2024 07:14:09 GMT

More info on the network topology is going to help!

Re: Can't access SmartHub 2 from different local subnet

Anonymous — Wed, 20 Mar 2024 07:38:20 GMT

BT Hubs block external ping, no idea on internal as I don't use one.

Re: Can't access SmartHub 2 from different local subnet

licquorice — Wed, 20 Mar 2024 08:21:30 GMT

You could try setting the subnet mask to 255.255.254.0 but it may not work as that will put the WAN and LAN in the same subnet.

That's assuming that the 2 subnets have the same first 2 octets.

Re: Can't access SmartHub 2 from different local subnet

WSH — Wed, 20 Mar 2024 09:47:44 GMT

You won’t be able to access it in a different subnet unless you are accessing it via another router.

What are you trying to use the SH2 for? As Crimliar said, without more information on what is connected to what it’s impossible for people give you any real answer.

Re: Can't access SmartHub 2 from different local subnet

TimCurtis — Wed, 20 Mar 2024 10:01:17 GMT

@jamespavett

I was using an SH2 for DV only and my Asus for everything else.

My SH2 was 192.168.2.1 and my Asus was 192.168.1.1 and I could access the SH2 from my home network with no difficulty at all.

I set my Asus to have a subnet mask of 255.255.252.0 , although 255.255.254 would work as well as @licquorice quotes.

Re: Can't access SmartHub 2 from different local subnet

WSH — Wed, 20 Mar 2024 10:47:54 GMT

@TimCurtis And I do (more or less) the same, but the real issue is that it was routing via the Asus to the other network.

Re: Can't access SmartHub 2 from different local subnet

jamespavett — Wed, 20 Mar 2024 11:45:23 GMT

@TimCurtis @Crimliar @WSH so to give you all a bit more background on my setup.

WAN -> Unifi Gateway -> Unifi Switch -> Smart Hub 2 (Running as AP)

I have two subnets / VLANs, well actually more but 2 relevant here.

Default 192.168.1.0/24 VLAN1 Subnet 255.255.255.0

Personal 10.44.2.0/24 VLAN2 Subnet 255.255.255.0

Just for testing, I moved by Hue Bridge (192.168.1.201) onto the Default / VLAN 1 network. From my PC on the Personal network (10.44.1.2) I can tracert the Hue Bridge no problem at all.

However I have my BT SmartHub 2 set to a static IP of 192.168.1.6 with DHCP and the firewall off as its only an AP, but I cannot hit this off any subnet other than the one the router itself is in, or access the web interface. Meaning I can reach the SmartHub 2 off any device in the Default subnet, but not any outside that. I did try putting my PC in the 192.168.x.x range and I could hit the SmartHub 2 no problem at all.

Seeing as I can still ping the Hue bridge, it does feel like something to do with the SmartHub 2 is blocking requests outside the local subnet, unless there is something else I am possible missing.

Re: Can't access SmartHub 2 from different local subnet

WSH — Wed, 20 Mar 2024 11:56:02 GMT

When you say "running as an AP" what exactly are you trying to do with it?

Re: Can't access SmartHub 2 from different local subnet

licquorice — Wed, 20 Mar 2024 11:59:51 GMT

Are you connecting the hub LAN to LAN or LAN to WAN?

Re: Can't access SmartHub 2 from different local subnet

jamespavett — Wed, 20 Mar 2024 12:00:24 GMT

I only want the SmartHub running as an access point to the network servicing WiFi connections.

Followed the guidance here:

https://community.bt.com/t5/Home-setup-Wi-Fi-network/Setting-up-a-Smart-Hub-2-as-an-Access-Point/td-p/2274422

But id quite like to be able to access the admin interface off of devices in different subnets on my network.

Re: Can't access SmartHub 2 from different local subnet

jamespavett — Wed, 20 Mar 2024 12:01:58 GMT

@licquorice I am connected via a LAN on the SmartHub 2 to a LAN on the switch.

Re: Can't access SmartHub 2 from different local subnet

WSH — Wed, 20 Mar 2024 12:03:19 GMT

Then the IP address on the SH2 needs to be part of the same subnet.

Re: Can't access SmartHub 2 from different local subnet

jamespavett — Wed, 20 Mar 2024 12:07:30 GMT

The IP address of the SH2 though is 192.168.1.6 which falls under the subnet of the Unifi router I am using, 192.168.1.0/24. So I would have thought traffic would be routes to it appropriately.

So 10.4.2.2 would go to 196.168.1.1 which then goes to 192.168.1.6. This works for a device at 192.168.1.201

Re: Can't access SmartHub 2 from different local subnet

licquorice — Wed, 20 Mar 2024 12:20:49 GMT

@WSH Exactly

Re: Can't access SmartHub 2 from different local subnet

WSH — Wed, 20 Mar 2024 12:20:50 GMT

Only if that traffic passes through the router. (Or possibly a layer 3 switch). That's what routers do, they connect different networks togther. Two devices in different subnets cannot talk directly to each other. That's the whole point of subnetting.

Edit: Anyway, I'll have to leave you to it. I need to go and do the shopping or I don't get to eat this weekend. (And I like eating even more than I like IT).

Re: Can't access SmartHub 2 from different local subnet

licquorice — Wed, 20 Mar 2024 12:35:33 GMT

@jamespavett

Ok, I've got a better picture in my head now. Yes, the hub is simply another device on your 192.168.1.xxx subnet and should be accessible as other devices on that subnet are.

Not entirely sure how you are managing to route from your 10 subnet to the 192 subnet in the first place though

Re: Can't access SmartHub 2 from different local subnet

jamespavett — Wed, 20 Mar 2024 12:48:00 GMT

@licquorice This is probably because my Unifi Gateway allows all traffic between subnets unless explicitly blocked. Hence when I can tracert from 10.4.2.2 to 192.168.1.201 without a problem for the Hue Bridge. But the exact same thing doesn’t work for the SH2

Each subnet has its own gateway, so 10.4.2.1 for VLAN2, 192.168.1.0 for VLAN1, and then I can route between them no problem.

To be it does feel like the SH2 is blocking anything not coming off the same local subnet, but potentially the request isn’t even getting to the device.

Re: Can't access SmartHub 2 from different local subnet

WSH — Wed, 20 Mar 2024 14:59:09 GMT

Ah right, so the gateway is acting as the router then. I see your problem. Misconfiguration in the gateway? I bet this is going to be something silly.

Re: Can't access SmartHub 2 from different local subnet

jamespavett — Wed, 20 Mar 2024 15:08:24 GMT

Yea the gateway is acting as a router for all of the vlans / subnets, and the old SH2 router is now purely acting as an AP.

So there’s nothing logical in your eyes @WSH that would prevent the SH2 being accessed from a separate subnet that it is on? I wasn’t sure if it might only accept requests within the 192.168 range.

Wondering if it could be down to where my ports are tagged somewhere, but I couldn’t see anything obvious earlier.