in my application the RUT240 works as a M2M access point for different wifi devices and one wired device.
One of the wifi devices needs to know the IP addresses of all other devices. Currently I have a shell script in /www/cgi-bin/ which returns /var/dhcp.leases and some modem data in a JSON format which is requested by said wifi client.
After a router reboot the wifi devices get a new IP, but the wired device not (which seems quite logical to me, since its connection is still established and there is no reason to ask for a new IP address).
One solution I thought of was to reduce the DHCP lease time to 2min so the wired client will ask for a new IP more frequently but that seems like a quite hacky way and also all other clients would do that.
The first 3 octets of the wired devices MAC address are known, since its always the same manufacturer.
I searched for a solution but programs like arp-scan or nmap aren't installed on the standard RUT OS. I also tried ping -b [broadcast IP] but there was no response from the wired device. As far as I know /proc/net/arp lists the same data as the DHCP lease file so this is also no help for me.
So is there any simple way to get the IP-address of the wired device after reboot?
This setup is replicated n-times so I'm looking for a general solution. Would be great if I can roll out a backup on all devices so no individual configuration is needed.