When the ADSL modem goes off, the network will become disabled

Question

In my personal network, I have connected all of my machines and also my ADSL modem to a network switch. The problem is that the machines get their IP addresses from the modem, thus when the modem is off, they can't connect to each other, because there is no modem they can get an IP address from it. How can I have my network enabled when the modem is off? Thank you.

Answer 1

You need to move your DHCP, and maybe DNS, to another machine. I have the following suggestions:

1. If you have an always-on machine/server this can easily be configured there.
2. If your switch is managed it may be able to do this for you
3. You can use a second router if you have one. Connect the LAN port to the switch and enable DHCP/DNS. Then disable your main router's DHCP
4. If none of the above are true, I suggest you get a mini-pc or a raspberry pi that will be always on and do this job only. This can also become a backup access point if you need wireless

In all cases you will still be off-line when the router goes down but you will have connectivity in the local network (LAN). Also, correct IP configuration is needed (setup the default gateway/router-option on the new DHCP server to point to the primary router)

If that is a once-off thing and your router does not go offline all the time, you can enable tethering on an Android mobile. This will do DHCP and DNS for you temporarily...