hostname and IP missing on router

[stuartiannaylor]

Running:
https://github.com/ayufan-rock64/linux-b...m64.img.xz

Controlling the rock64 via Putty - SSH

When first connecting:
apt update
apt upgrade
Then I change /etc/hostname and in /etc/hosts I add my fixed public IP with the hostname from /etc/hostname.

I then do:
apt remove --purge network-manager
make sure resolvconf is not installed
then:
rm /etc/resolv.conf
then make a new resolv.conf:
nano resolv.conf adding my 2 nameservers IP addresses and save.

then (I want to have complete control of the IP of the rock64 with no odd interference from other files/scripts that I don't know about):
systemctl disable dhcpcd
systemctl enable networking (in order to get back to the "oldfashioned way")

then:
nano /etc/network/interfaces.d/eth0 (I use only the wired rock64 LAN port)
I enter:

allow-hotplug eth0
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static
     address XX.XX.XX.XX
     netmask XXX.XXX.XXX.XXX
     gateway XX.XX.XX.XX
     
The IP addr and mask are not on the same network as my local network.
It is created as a 2nd static IPv4 route on the router (fritzbox 7490) with 5 fixed IP addresses. I am not able to add the external IP and MAC as it is not on the same network as the fritzbox.

I then reboot the rock64.
When looking at the network connections tab in the fritzbox I don't see the rock64 (with it's new hostname and external IP) - tried several reboots of the rock64 and the router.

FYI when I do all this from a Rpi, Bpi, odroid or olimex I always see each of them on the fritzbox, with their hostname and external IP.

What can/could cause the missing fritzbox entry from the rock64?
It puzzles me and is annoying, as I need to create port permissions for the rock64 through the fritzbox from outside.

Its not just network manager that makes resovl.conf dynamic.

/etc/hostname me.my.lan
/etc/hosts
127.0.0.1 localhost
127.0.1.1 me.my.lan
x.x.x.x     me.my.lan
x.x.x.x = static lan connection but why you disbaled dhcpd ?

/etc/network/interfaces.d/ethx
# The primary network interface
auto eth0
iface eth0 inet static
    address 10.0.0.41
    netmask 255.255.255.0
    network 10.0.0.0
    broadcast 10.0.0.255
    gateway 10.0.0.1
    dns-nameservers 10.0.0.1 8.8.8.8
    dns-domain my.lan
    dns-search my.lan


That is all you need to do infact if the fritz box is controlling then it prob should be dhcp.

Plus your running a prerelease image that probably doesn't work anyway.