Network devices telling the router their name

[Julian]

I'm setting up my new Virgin 3.0 Hub which has instigated a bit of a tidy-up of my network. I'm using some DCHP reservations to bind various devices to known fixed IP addresses and also shuffling around addresses on things that were already static so I've been spending a lot of time hitting refresh on the "Connected Devices" tab and I noticed that for the "Device name" for some of my connected devices the router shows "Unknown" whereas others show meaningful names such as "Google-Home-Mini", "HarmonyHub" etc.

I'm wondering what mechanism/protocol is used by the device to give the router a device name to use and whether I can get rid of any of the "Unknowns". I don't think I can for some of them. One of my "Unknown" devices is an IPTV satellite tuner so I can't control the firmware on that, another is (slightly disappointingly) my nVidia Shield - as a big generally well-respected company I would have hoped they would have attended to little details like this. My third "Unknown" device however is my Raspberry Pi running Linux (Rasbian) which I do have total control over (apart from firmware on the Ethernet interface itself) so I am wondering if there is any config file where I could set a name for it to announce to the router.

Interestingly I note that on the Virgin router's list of connected devices two are "Unknown" whereas the third is "unknown". The two "Unknowns" have both been set to static IP addresses on the devices themselves (my preferred approach) whereas the "unknown" device is using a DHCP reservation to get its address. Maybe that's just coincidence. All the Unknown/unknown devices are hard-wired by the way.

If I did know a bit more about how this worked I might also just possibly be able to fix the nVidia Shield too. nVidia are pretty good with frequent firmware updates so just possibly filing a low-priority bug report requesting it identify itself properly to a router might get implemented at some point and it might help me file a better report if I could be a bit more precise in what I want them to fix.

- Julian

[Slarti]

I can actually name, or rename stuff on my router control page, but it not a Virgin one.

Slarti

[pochisoldi]

I'm setting up my new Virgin 3.0 Hub which has instigated a bit of a tidy-up of my network. I'm using some DCHP reservations to bind various devices to known fixed IP addresses and also shuffling around addresses on things that were already static so I've been spending a lot of time hitting refresh on the "Connected Devices" tab and I noticed that for the "Device name" for some of my connected devices the router shows "Unknown" whereas others show meaningful names such as "Google-Home-Mini", "HarmonyHub" etc.

I'm wondering what mechanism/protocol is used by the device to give the router a device name to use and whether I can get rid of any of the "Unknowns". I don't think I can for some of them. One of my "Unknown" devices is an IPTV satellite tuner so I can't control the firmware on that, another is (slightly disappointingly) my nVidia Shield - as a big generally well-respected company I would have hoped they would have attended to little details like this. My third "Unknown" device however is my Raspberry Pi running Linux (Rasbian) which I do have total control over (apart from firmware on the Ethernet interface itself) so I am wondering if there is any config file where I could set a name for it to announce to the router.

Interestingly I note that on the Virgin router's list of connected devices two are "Unknown" whereas the third is "unknown". The two "Unknowns" have both been set to static IP addresses on the devices themselves (my preferred approach) whereas the "unknown" device is using a DHCP reservation to get its address. Maybe that's just coincidence. All the Unknown/unknown devices are hard-wired by the way.

If I did know a bit more about how this worked I might also just possibly be able to fix the nVidia Shield too. nVidia are pretty good with frequent firmware updates so just possibly filing a low-priority bug report requesting it identify itself properly to a router might get implemented at some point and it might help me file a better report if I could be a bit more precise in what I want them to fix.

- Julian

It's done via DHCP. The client sends option information to the DHCP server (on your router) with the request for an IP address.
Some boxes simply provide the last IP address they received (in the hope of getting the same address next time around). Other boxes provide a hostname - with Android etc. this usually ends up being the device name.
Some options are optional, hence the occasional "unknown" or blank.

You need to remember that in a domestic situation DHCP only works on the LAN (it's effectively a layer 2 protocol), and so there's no information leakage onto t'interweb. Or put another way DHCP isn't a routed protocol so the DHCP request/reply packets can't get onto the internet.
(Note that I say "domestic situation" - there is a feature called DHCP relay, but it's a feature that isn't needed or provided for in a domestic/very small office settting).

PochiSoldi

[yorkshirelad1]

I'm setting up my new Virgin 3.0 Hub which has instigated a bit of a tidy-up of my network. I'm using some DCHP reservations to bind various devices to known fixed IP addresses and also shuffling around addresses on things that were already static so I've been spending a lot of time hitting refresh on the "Connected Devices" tab and I noticed that for the "Device name" for some of my connected devices the router shows "Unknown" whereas others show meaningful names such as "Google-Home-Mini", "HarmonyHub" etc.

[snip]

- Julian

I had this in a domestic set up. Sky router, with a Hive (home heating) hub which was a wired connection into the router and showed up in the "Connected Devices" table as "Unknown", which was a little annoying as I wanted to know what devices were connected. A few postings on the Hive forums and lo and behold a few months later, the Hive hub is showing up in my router as "MyHive" (or something similar, I can't remember the exact title and I'm not near the router at the mo). I wasn't the only one complaining of this on the Hive forums, so maybe Hive got round to it eventually.

On a similar vein, some android phones only seem to offer only a really long fairly meaningless string/description in the router's connected devices table and no way to change it (to e.g. FredsPhone) unless you root the phone.

[Julian]

It's done via DHCP. The client sends option information to the DHCP server (on your router) with the request for an IP address.
Some boxes simply provide the last IP address they received (in the hope of getting the same address next time around). Other boxes provide a hostname - with Android etc. this usually ends up being the device name.
Some options are optional, hence the occasional "unknown" or blank.
...

Is there also some other method though because my PC has a static IP address set in the Windows 10 network settings and it still shows it's meaningful name in the Virgin router's list. I'm assuming that with a static IP set in Windows the PC doesn't even attempt to contact the router's DHCP server for an IP address (but maybe I'm wrong on that) in which case some protocol other than DHCP must be getting the device name from my PC up to the router.

Is there some sort of introduction/test protocol where, once the client has its IP info either from the DCHP server or set by the admin as static data (IP address, gateway, DNS server and netmask) it introduces itself to the gateway or DNS server address (in domestic settings usually the same, at least for the primary DNS) and at that point might be able to tell the router its meaningful name?

- Julian

[Julian]

I had this in a domestic set up. Sky router, with a Hive (home heating) hub which was a wired connection into the router and showed up in the "Connected Devices" table as "Unknown", which was a little annoying as I wanted to know what devices were connected. A few postings on the Hive forums and lo and behold a few months later, the Hive hub is showing up in my router as "MyHive" (or something similar, I can't remember the exact title and I'm not near the router at the mo). I wasn't the only one complaining of this on the Hive forums, so maybe Hive got round to it eventually.

On a similar vein, some android phones only seem to offer only a really long fairly meaningless string/description in the router's connected devices table and no way to change it (to e.g. FredsPhone) unless you root the phone.

Nice to hear that some companies do listen. It makes me a bit more optimistic that a bug report filed with nVidia might be actioned in some future firmware release.

- Julian

[StepOne]

Some options are optional...

You don't say

StepOne

[pochisoldi]

It's done via DHCP. The client sends option information to the DHCP server (on your router) with the request for an IP address.
Some boxes simply provide the last IP address they received (in the hope of getting the same address next time around). Other boxes provide a hostname - with Android etc. this usually ends up being the device name.
Some options are optional, hence the occasional "unknown" or blank.
...

Is there also some other method though because my PC has a static IP address set in the Windows 10 network settings and it still shows it's meaningful name in the Virgin router's list. I'm assuming that with a static IP set in Windows the PC doesn't even attempt to contact the router's DHCP server for an IP address (but maybe I'm wrong on that) in which case some protocol other than DHCP must be getting the device name from my PC up to the router.

Is there some sort of introduction/test protocol where, once the client has its IP info either from the DCHP server or set by the admin as static data (IP address, gateway, DNS server and netmask) it introduces itself to the gateway or DNS server address (in domestic settings usually the same, at least for the primary DNS) and at that point might be able to tell the router its meaningful name?

- Julian

My money is on one of the following:
a) The Windows box in the past has made a DHCP request (before the static IP was configured), and the router has remembered the PC's MAC address +hostname and has stored them. This is a function of the router, not the PC.
b) The Windows box doing a gratuitous DHCP request to see if any DHCP server responds. This is triggered by the PC.

The only way to determine what is going on is to run Wireshark on the LAN on one PC, do a filtered capture and then boot up the PC with the static address and see whether the router or the PC send out DHCP packets to each other

If you see nothing being sent then it's case (a)
If you the Windows box sending data, it's case (b).

In the the (B) case, Microsoft are notorious for having Windows boxen doing things without telling you and you only find out if you look (as you've seen), or you have an unusual setup which causes Microsoft's mucking around to break. (e.g. sending out ARP requests when bringing up an interface to discover whether the interface is using a duplicate IP - works fine normally, but not when the customer's network people are screwing around using SNAT on their router...). These "things" are usually to proactively detect problems and tell you what's been found, rather than just sitting there broken.

[pochisoldi]

Some options are optional...

You don't say

StepOne

And some options if not filled make for a pretty useless DHCP server, and are therefore "non optional options"

For example for most users the Default router and DNS server options aren't really optional, because you (a) can't get onto the internet without the default router, and (b) will have a hard time navigating around without DNS.

[Julian]

My money is on one of the following:
a) The Windows box in the past has made a DHCP request (before the static IP was configured), and the router has remembered the PC's MAC address +hostname and has stored them. This is a function of the router, not the PC.
b) The Windows box doing a gratuitous DHCP request to see if any DHCP server responds. This is triggered by the PC.
...

Thanks. It's definitely not (a) because the router is only 1 day old and my PC has had a static address ever since the day I first built it about 9 months ago so this router has definitely never had a deliberate (as opposed to the scenario (b) covert) encounter with my router's DCHP so it must be (b).

My Pi has its static address defined in the /etc/dchpcd.conf file so I think Raspbian does do a DCHP interaction first and I can probably sort that out by exploring the options in that file and probably set a name field somewhere. The nVidia Shield is probably a bug report but I'll have a go at setting it to dynamic IP briefly, have it get an address, and then set it back to static to see if that does anything.

I have to say though that the Virgin router is a bit erratic on it's local network stuff. I just did a reboot and my Freeview tuner on 192.168.0.19 wasn't listed as a connected device despite the fact that I could ping it and view channels from my PC so it was definitely on the network. Still, the internet connection is good and stable so far and all my devices are migrated across and working correctly on their new IP addresses so hopefully I won't really need to look at the router's admin page much any more.

- Julian

[StepOne]

Some options are optional...

You don't say

StepOne

And some options if not filled make for a pretty useless DHCP server, and are therefore "non optional options"

For example for most users the Default router and DNS server options aren't really optional, because you (a) can't get onto the internet without the default router, and (b) will have a hard time navigating around without DNS.

Apologies ps, it just made me laugh when I read it, wasn't meant to be a dig at you

[pochisoldi]

You don't say

StepOne

And some options if not filled make for a pretty useless DHCP server, and are therefore "non optional options"

For example for most users the Default router and DNS server options aren't really optional, because you (a) can't get onto the internet without the default router, and (b) will have a hard time navigating around without DNS.

Apologies ps, it just made me laugh when I read it, wasn't meant to be a dig at you

Bit of a Rumsfeld moment...

"There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we don't know we don't know. "