Fallback Ip ( if no DHCP detected, Give a static IP )

General Discussion
1

Hi all, I’m pretty new to the Linux ecosystem…But I’ve some base and I manage with step by step :smile: tutorial but for now I cant find what i need

I’m searching a way to add a script into "etc/network/interfaces " for when i connect my SBC to a network it detect the router and use the DHCP address but if I’m connecting it to my laptop I want it to use some priority, first boot try 10-15sec to use any available DHCP if no, to Fall on a pre-configured Static IP.

How I can achieve that ?

image
image1095×537 10.4 KB

2

Something you can check

https://forums.raspberrypi.com/viewtopic.php?t=84767

3

didnt work but thanks

4

On RPi OS, dhcpcd is used as only network tool, while we use ifupdown and the isc-dhcp-client. I am not aware of an automatic fallback via ifupdown resp. /etc/network/interfaces, but the DHCP client config might have something: dhclient.conf(5) — isc-dhcp-client — Debian bookworm — Debian Manpages

The prepend statement sounds like it would serve your needs: Have certain option applied first, then have the DHCP server overriding them, if there is one.

5

I found it, and it’s working great :slight_smile:

I Added this code

timeout 10;
lease {
  interface "eth0";
  fixed-address 10.0.0.10;
  option subnet-mask 255.255.255.0;
  option routers 10.0.0.10;
  renew 2 2053/1/12 00:00:01;
  rebind 2 2053/1/12 00:00:01;
  expire 2 2053/1/12 00:00:01;
}

image
image1171×398 5.1 KB

1 Like