In reply to a post by MrSaffron:

Something is not right, managed switches should run for years once configured, so either you've messed something up or its broke.

Recommendation - send it back and just use an unmanaged switch. Unless you fancy a day spent figuring it out

I have got a netgear unmanaged type so I may well end up using that. I was hoping it was going to be far more straightforward and help me see more about my network, but it's just odd, perhaps it doesn't like the PlusNet router for some reason.

I have tried the other fixed range the PN router offers ie 172.16.0.64 - 172.16.255.254 and it's on that now. I have initially set the Netgear switch to DHCP enabled as that was the more stable setting than specifying an IP address.

Am i right in thinking that in general when you Enable a Switches DHCP that is for instance in a setup like mine ie connected to a modem/router, that all the switch does is "say" <include me into the DHCP pool> .
Plus when you Disable the Switches DHCP it just allows you to assign the switch a fixed IP address.
What I'm trying to ask is, am I right in thinking that these cheaper managed switches don't have the same sort of DHCP function as a modem/router does in as much as the switch doesn't assign IP addresses as the modem/router does. If I am right the option to enable/disable DHCP on the switch isn't actually as literal as it is meant on a modem/router?

A DHCP client performs the first and third parts of a four-stage process that is a more complicated, though entirely straightforward, version of what you mean by "say".

The phases are 'Server Discovery', 'IP lease offer', 'IP lease request' and 'IP lease acknowledgement' - the second and fourth stages being performed by the DHCP server. This is commonly known as "DORA": discovery, offer, request, acknowledgement.

The client needs an IP so looks for any available DHCP server, the server receives this discovery request and offers an available IP from its DHCP pool, the client confirms it will take that IP and the the server acknowledges this.

As you commendably seem to be persevering with this (sorry, that sounds patronising and it's not meant to!) having as clear as possible an idea of what is actually going on will help. Moreover, this points out the difference between a DHCP client and a DHCP server in case there is any confusion there.

Which leads us into your last paragraph... no, switches don't work the way a modem/router does, and they don't assign IP addresses. They work at the Data-Link layer, sending data as 'frames' between MAC addresses, whereas routers work at the Network layer *, sending data as 'packets' between IP addresses.

As others have already said, you should manually assign your switch an IP that is outside the DHCP pool on your DHCP server (your PlusNet router), but it can get an IP via DHCP - and indeed probably defaults to that out-of-the-box for easier setup - and in this scenario it is functioning as a DHCP client. It is doing the D and R in 'DORA', not the O and A.

So many consumer devices these days are jack-of-all-trades, at least if you want them to be, so despite what I said above about layers 2 and 3 it is possible that your managed switch has a DHCP server bundled with it and that when you say you are "enabling DHCP" you are turning on an additional DHCP server (to the one on your router) rather than telling the switch to get its IP via DHCP. If so, this would be <Trump>Bad!</Trump>

As your PlusNet router is already functioning as your DHCP server you don't want anything else trying to do the same job. I'm oversimplifying but you can think of them as fighting over the DHCP clients and potentially causing DHCP failures. It could be at least part of your problem, if not the whole thing. Another reason to manually assign the switch's IP - so every 'DHCP' option on your switch can be disabled for minimal confusion.

* N.B. for other techies: yes, this is not the only over-simplification here but I have deliberately left out any mention of Layer 3 switches, subnets, VLANs, superscope etc. to try not to complicate matters any more than necessary

Edited by deleted (Sat 18-Nov-17 16:38:22)

In reply to a post by Vorlon:

Am i right in thinking that in general when you Enable a Switches DHCP that is for instance in a setup like mine ie connected to a modem/router, that all the switch does is "say" <include me into the DHCP pool> .

Essentially yes, but it would be better to say that the switch will look for a DHCP and then get assigned an address.

Plus when you Disable the Switches DHCP it just allows you to assign the switch a fixed IP address.

Yes, you have to assign an IP address etc.

What I'm trying to ask is, am I right in thinking that these cheaper managed switches don't have the same sort of DHCP function as a modem/router does in as much as the switch doesn't assign IP addresses as the modem/router does.

I doubt any switch would act as a DHCP server.

If I am right the option to enable/disable DHCP on the switch isn't actually as literal as it is meant on a modem/router?

Correct, the switch acts in the same way as almost everything else you can connect to an IP network. Devices that don't let you assign a fixed address are unusual.

Assigning a fixed address to a switch just makes it easy to access the web management. If you also assign a fixed address to your PC or whatever you are using to contact the switch, you would be able to make contact even if your router is not working, so long as there is a physical path.

Many thanks G2 Covers for the in depth explanation and thanks Michael for responding to my questions. Whilst I'm a bit of a geek in other areas, networking has always alluded me as I've not been involved with it during my career.

But these days with so many devices having data connectivity via Wifi/Wired and the market accommodating nicely I wanted to brush up on it, but now I'm wondering if this Netgear Smart Switch was a wise choice. I would have stuck with WiFi but with so many other connections in the building I found peak times the worst for things like TV video streaming.

The state of play at present is that it's been working without issues since this morning. The current set up is :-

PlusNet Hub One: DHCP IP range set to it's pre determined second option: 172.16.0.64 - 172.16.255.254
PlusNet Hub One: Own IP Address: 172.16.0.1
PlusNet Hub One: Own SubNet Mask: 255.255.0.0

Netgear GS108Ev3: It's IP Address: 172.16.0.65 DHCP is Enabled on this Switch.
I know you've all suggested this is a bad idea and I understand why, but oddly it appears to be the most stable setup.

The Odd thing was though when I did as Michael had written literally to the letter , ie set a range of IP addresses on the PN HH One and then set a fixed IP address on the switch which was outside of the PN One's set DHCP IP address range - the network would fallover after around 10 minutes. The thing that was very different is that the Netgear Utility would still access the Switch which it wouldnt do before. Also I found I could reset the switch from the Utility without having to muck around with a cotton bud stem or having to cycle the power. Plus the connectivity task bar Icon remained connected, but of course the internet wasn't being routed.

Any theories?
Should I throw the towel in and just connect an unmanaged switch as I do have a Netgear GS208 somewhere or would it be advisable to steer clear of the Netgear switches and Purchase something like a Dlink, Linksys or TPLink?

Edited by Vorlon (Sat 18-Nov-17 15:57:20)

The subnet mask is important. I would set the router subnet mask to 255.255.255.0 and make sure that is what DHCP then allocates to all your devices such as your PC etc. I would do that for both the 172.16.x.x and the 192.168.x.x type addresses.

If you don't, you may find that thinks like Windows workgroups and Samba will not work. That may give trouble using local file servers (NAS).

In reply to a post by Vorlon:

it requires resetting at least every day.

There's been a lot of talk about how to go about allocating an IP address to the switch, but you don't actually say what goes wrong "when it needs resetting". Not in the first post, but you slightly allude to a problem later on.

What actually goes wrong? What are the symptoms?

Yes,when it goes wrong, the devices like my PC, TV , Laptop etc will lose connectivity with the switch and for instance the windows taskbar icons will indicate a connectivity error by displaying yellow mark.
Also the switch will indicate using the Netgear ProSafe software an Apipa address under the heading of "Located on IP Network" which normally indicates the IP address of my Laptop which I have the said Netgear ProSafe software installed on.

Although when the Netgear Software will indicate this Apipa address I cannot use this utility to reboot the Switch, so that has to be reset via its reset switch or by recycling power.

It's still working at present using the PN home hubs second IP range selection choice of 172.16.0.64 - 172.16.255.254, where I believe a subnet mask of 255.255.0.0 must be used and tht subnet mask is indicated too in the switch software. Also the switches "DHCP" is enabled.

So far it hasn't gone wrong on these settings, but if these IP's are not in an ideal address range for other hardware then i assume I'll see other issues down the road and maybe the unmanaged switch is the way to go?

Edited by Vorlon (Sun 19-Nov-17 08:46:02)

Unfortunately I lost connectivity from the switch to all other devices after turning my PC on last night which is also connected to the switch via Cat 6 cable and at 1Gbps. In this case it was the same issue with the original set up ie when the Plusnet Hub One was set to its default IP range. I had been trying the Secondary range offered for selection by the PN HH ie 172.16.0.64 - 172.16.255.254 and my laptop and Smart TV also both connected to the switch had been working to that point. Again network connectivity was lost rather than the Internet going across it, indicated by the Ethernet taskbar Icons displaying the yellow mark.

I appreciate all the help you guys have given and I suppose there is the possibility that the Netgear switch doesn't play nice with the Home Hub. I wanted to at least get the switch going with the PN HH before I changed over to a TPlink VR900 VDSL/Router just to know if technical support ever insisted I had to use their router for fault finding I'd know how things were.

I have seen many a post with people commenting on switches defaulting to the Apipa addresses, but have found nothing that I think quite fits with my scenario.
Anyway I think the best bet for me is to use the Netgear GS208-100UKS unmanaged switch which I bought awhile ago and hope it'll be ok with the PlusNet HH.

The whole idea why I went for a managed switch is not that I really wanted to manage it, but rather I wanted something via it's software to give me an idea on the seperate connected items data usage, particularly when it comes to HD TV streaming. This problem for me switch does give some basic info via the Netgear Prosafe software, but it's very limited and to be honest i did not know what to expect from an entry level managed switch, as it's all fairly new ground for me.

Thanks for those who helped anyway, I've got a better understanding than I did have!

If the fail is linked to a PC always turning on, then it may be something around the IP address the PC is using or trying to use clashing.

In reply to a post by Vorlon:

Yes,when it goes wrong, the devices like my PC, TV , Laptop etc will lose connectivity with the switch and for instance the windows taskbar icons will indicate a connectivity error by displaying yellow mark.

If your devices are losing connectivity with other devices on the switch, then that is a problem with L2 switching, not with L3 IP address routing.

It looks like the switch *only* uses its L3 IP address as the target for maintenance activities. If that IP address changes, it should only affect attempts at maintenance, and it shouldn't affect any layer 2 switching activities.