Getting the router to actually assign an IP address to the server
You would typically want to use static ip addresses for servers (because if you use DHCP the IP is gonna change sooner or later, and it’s gonna be a pain in the butt).
IIRC dnsmasq is configured to assign IPs from .100 upwards (unless you changed that), so you can use any of the IPs up to .99 without issue (you can also assign a DNS name to the IP, of course).
all requests’ IP addresses are set to the router’s IP address (192.168.3.1), so I am unable to use proper rate limiting and especially fail2ban.
Sounds like you are using masquerade and need DNAT instead. No idea how to configure that in openwrt - sorry.
You would typically want to use static ip addresses for servers (because if you use DHCP the IP is gonna change sooner or later, and it’s gonna be a pain in the butt).
IIRC dnsmasq is configured to assign IPs from .100 upwards (unless you changed that), so you can use any of the IPs up to .99 without issue (you can also assign a DNS name to the IP, of course).
Sounds like you are using masquerade and need DNAT instead. No idea how to configure that in openwrt - sorry.