[SOLVED] Mom is moving in - need separate subnet. HELP!

[nancyh1980]

Hi there,

I know little enough to be dangerous and wrong most of the time.

I have AT&T modem-router. Ipconfig/all on my desktop shows:
IP: 192.168.1.201
GW: 192.168.1.254
Subnet Mask: 255.255.255.0
DNS1: 192.168.1.254
DNS2: 8.8.8.8

Now my 76yo mom is moving to guest room. She has the same medical machine like mine. Since we can't have (2) of the same machines within the same subnet (the app would not know which machine to logon to and I confirmed this with the manufacturer) I would like to setup hers in a different subnet like 192.168.21.x.
I purchased a TP-Link router and configured that router:
GW: 192.168.21.1
Subnet Mask: 255.255.255.0
DNS1: 192.168.21.1
DNS2: 192.168.1.1
Different SSID than one from the AT&T modem-router.
A verified good cat5 cord between AT&T ETHERNET port and TP-Link INTERNET port.

Her medical machine, in DHCP mode, does not get any internet when plugged into TP-Link ETHERNET port. It, however, gets internet when plugged into my AT&T router-modem Ethernet port.
Also, when I jump onto her SSID, my phone gets NO internet.

May I know what I am doing wrong?
If needed, I can configure her machine in static IP.
Many thanks in advance.

 

[SamirD]

Do the medical machines need Internet access too? Reason I ask is because if you don't, you can just put in a static IP for her machine and tell her app the IP and it should work even on your at&t equipment.

Otherwise, it sounds like you're wired up correctly except I wouldn't mess with the dns settings. You need to see if the tp-link is getting an address from the at&t router which will be a 192.168.1.xxx number.

Also, there might be a bit of a problem as technically anything connected to her router could reach your machine if it specifies your 192.168.1.xxx ip address.

 

[nancyh1980]

Hi Samir,
Both machines need internet to send data for monitoring.
The only equipment attached to her side would the the machine and her laptop which should not see my side!
I will try changing the dns back and see.
Thanks

 

[SamirD]

I see. Hmmm...which AT&T gateway do you have?

 

[ss202sl]

Ask them how they deal with the equipment in the hospital - asumption is that hospitals have several on the same network.

 

[Alabalcho]

The simplest would be to get cheap router, plug it into AT&T router, and connect your mom' equipment to the second router. Configure her phone to connect to that router, too.