Similar topic were discused here, but I think not my case. So briefly situation - I had a router on local IP i.e. 192.168.100.1/23. One day I had established new one and set it's IP to 192.168.101.1/23 (so still the same network) and started to move clients one by one to the new router and then the old router was removed. The old/new router is running services including DNS and NTP server. Many devices in the network has static settings of DNS or NTP to IP of old router 192.168.100.1/23. So first solution to keep reachability of DNS nad NTP was to set old IP 192.168.100.1/23 of the router to local LAN interface of the new router together with the new IP 192.168.101.1/23.
Now I would like to remove the old IP from the new router, but keep reachability of NTP and DNS for devices which refer to old IP. Normaly it would be simple task for dst-nat with action redirect. But the problem is that the redirected old IP is in the same subnet like the current router IP and mentioned solution does not work. Am I able to make it work without asigning the old IP to current router LAN interface? Thanks for help!