DNS question

[bigegg]

I have investigated further (now I have a better knowledge of the terminology), and this came up:

Devices connected to Extender are showing wrong MAC addresses - Home Network Community

Hi All, I am having a strange issue with MAC addresses which are connected to extender. First thing first. My setup is as follow: Ground Floor: Router ----> SERVER2016 (DHCP, DNS and Unifi Controller ) [Cabbled to ro

community.tp-link.com

Basically, stuff connected through the extender have a "virtual" MAC address assigned, and it can't be turned off.

The "reserved IP" assignation works fine, as far as it goes: it's just that any device is given one of two different IP addresses (by the DHCP server in the router) depending upon whether it is connected via the extender or straight to the router.


So I'm back to my original question:
How do I make a hostname point to one of two different IP addresses, depending upon which one is active?


I'm running a Netgear nighthawk r9000 router with stock firmware.
It doesn't do mDNS, unfortunately.

 

[carbon]

This is from the user guide for the re360

3. 4. Specify DHCP Server Settings
By default, the DHCP (Dynamic Host Configuration Protocol) Server is enabled and the extender acts as a DHCP server; it dynamically assigns TCP/IP parameters to client devices from the IP Address Pool. You can change the settings of the DHCP Server if necessary.

 

[bigegg]

This is from the user guide for the re360

3. 4. Specify DHCP Server Settings
By default, the DHCP (Dynamic Host Configuration Protocol) Server is enabled and the extender acts as a DHCP server; it dynamically assigns TCP/IP parameters to client devices from the IP Address Pool. You can change the settings of the DHCP Server if necessary.

It's turned off.
DHCP is being done by the router.

 

[carbon]

I’ve not encountered this issue myself but have found this on the Tp link site

 

[MoreWellie]

Basically, stuff connected through the extender have a "virtual" MAC address assigned, and it can't be turned off.

The "reserved IP" assignation works fine, as far as it goes: it's just that any device is given one of two different IP addresses (by the DHCP server in the router) depending upon whether it is connected via the extender or straight to the router.


So I'm back to my original question:
How do I make a hostname point to one of two different IP addresses, depending upon which one is active?

I think you need to address this from a slightly different direction

your DHCP server will have a "pool" of IP addresses which it can assign and these are usually configured as a start address e.g. 192.168.1.100 and then a count which controls how many addresses are being handed out

As you are using a simple network every device needs an address starting 192.168.1 the number on the end has to be unique for each device. The router is often assigned 192.168.1.1 depending on what your DHCP pool addresses are there are often addresses which remain unused

if your DHCP pool starts at 192.168.1.20 and allows for say 200 devices this reserves 192.168.1.20 through to 192.168.1.219 This means there are some unused address at the beginning and end of this range which can be used on devices which have manually been configured with these "static" addresses. I.E. they don't use DHCP but are configured to always have one of the unused addresses. You need a different address for each such device so (in my example case) I would start with 192.168.1.2 and then 192.16.1.3 for the next one and so on up to 192.168.1.19 If this isn't enough then jump up to 192.168.1.220 and on from there

You can do this for wifi devices providing they have a configuration page/mechanism where you can get in to their setup. Once configured they should always use the same address regardless of whether they are connected to the router or the extender

These static addresses are also ideal for printers that connect to the network as older printer drivers were especially bad at tracking printers that changed their IP address

Of course this isn't an ideal world so sometimes devices lose their configuration but this doesn't happen that often and is immediately obvious when they stop working you then have to find them and reconfigure them

 

[bigegg]

I think you need to address this from a slightly different direction

your DHCP server will have a "pool" of IP addresses which it can assign and these are usually configured as a start address e.g. 192.168.1.100 and then a count which controls how many addresses are being handed out

As you are using a simple network every device needs an address starting 192.168.1 the number on the end has to be unique for each device. The router is often assigned 192.168.1.1 depending on what your DHCP pool addresses are there are often addresses which remain unused

if your DHCP pool starts at 192.168.1.20 and allows for say 200 devices this reserves 192.168.1.20 through to 192.168.1.219 This means there are some unused address at the beginning and end of this range which can be used on devices which have manually been configured with these "static" addresses. I.E. they don't use DHCP but are configured to always have one of the unused addresses. You need a different address for each such device so (in my example case) I would start with 192.168.1.2 and then 192.16.1.3 for the next one and so on up to 192.168.1.19 If this isn't enough then jump up to 192.168.1.220 and on from there

You can do this for wifi devices providing they have a configuration page/mechanism where you can get in to their setup. Once configured they should always use the same address regardless of whether they are connected to the router or the extender

These static addresses are also ideal for printers that connect to the network as older printer drivers were especially bad at tracking printers that changed their IP address

Of course this isn't an ideal world so sometimes devices lose their configuration but this doesn't happen that often and is immediately obvious when they stop working you then have to find them and reconfigure them

This is what I was referring to above (when I said "devices can request an IP address, rather than having one assigned") -

That's going to be the plan (if I can) for now: I was hoping that I could do it all in one place, rather than having to individually configure a load of devices, though.

Thanks!

 

[MoreWellie]

rather than having to configure a lot of devices, though

you only have to manually configure the ones that might wander between the extender and router and even then only if you need access to them

The devices that do the accessing (internet or local) can stay on DHCP you just need to assign static addresses to the ones you need to access through the local dns

 

[Dev]

DHCP address reservations are definitely the way to go.
MAC randomisation should only affect wifi scanning, not connecting. When a DHCP lease is requested a device provides its real MAC which doesn’t change.

An exception is Virtual machines, docker, promox etc. As they don’t have actual MAC addresses for their virtual interfaces they can change if the container is restarted.

 

[bigegg]

DHCP address reservations are definitely the way to go.
MAC randomisation should only affect wifi scanning, not connecting. When a DHCP lease is requested a device provides its real MAC which doesn’t change.

An exception is Virtual machines, docker, promox etc. As they don’t have actual MAC addresses for their virtual interfaces they can change if the container is restarted.

I'm already reserving addresses for various devices.
The issue is, I have to reserve two different IP addresses - one for each potential MAC address (one for direct connection, one for connection via WiFi extender).
I want to type a hostname in my browser, and have it connect to whichever IP address is valid for that device.

 

[Dev]

The wifi extender is masking the correct MAC of your devices. It shouldn’t. How annoying.

TL-WR702N in repeater mode masking MAC addresses - Home Network Community

Region : CanadaModel : TL-WR702NHardware Version : V1Firmware Version : ISP : My main router is a Linksys E3000 on which I have replaced the stock firmware with DD-WRT. I have written a monitoring script for DD-WRT that allows me to monitor the usage

community.tp-link.com

 

[bigegg]

The wifi extender is masking the correct MAC of your devices. It shouldn’t. How annoying.

TL-WR702N in repeater mode masking MAC addresses - Home Network Community

Region : CanadaModel : TL-WR702NHardware Version : V1Firmware Version : ISP : My main router is a Linksys E3000 on which I have replaced the stock firmware with DD-WRT. I have written a monitoring script for DD-WRT that allows me to monitor the usage

community.tp-link.com

Yes...