route traffic from src IP to dst IP on the same subnet

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Hello,

Is there a way to redirect all traffic going to an IP to another IP on the same subnet?

I need to decommission a DNS server. 192.168.1.4, and unfortunately I can't reuse the IP on any of the other existing DNS servers, nor I can create a new VM (to assign this IP) due to licensing issues. What I would like to do is, use this .4 IP on any other network device, and configure the device to forward that traffic from .4 to 192.168.1.42

Pretty much this client doesn't want to spend $ on new hardware. So can't buy a new license for the vm, nor a new baremetal server, nor new layer 3 switch. I can only play with what they have already which is Cisco routers, ASA's, layer 2 switches, Hyper-V server.

obviously, I know that the purpose of routing is to connect different networks. However, this is a special circumstance, so I'm looking for a workaround, or use of NAT or bridging or anything else that you might have used in the past to solve something like this.

Thank you!

@Jorge-Sosa-0,

If DNS IP information is being handed out using DHCP, you could change the DHCP lease to include your new DNS server's IP (192.168.1.42) as a DNS server. Get everyone to renew the lease to get the new DNS information. Then decommission your 192.168.1.4. You would still have to do a manual reconfig of static VMs or boxes with the NEW DNS information. But it sounds as if you already have DNS running on other servers...So how are those accessed by the current LAN hosts?

A Cisco router is not going to help you in this instance since the DNS server is on the same subnet and not going to another subnet. NAT is not going to help either because we're not doing any inside or outside interfaces. ASA isn't helping because you're still on the trusted network within the same trusted network.

So someone else may have a better solution but I think what I mentioned may be considered.

I agree with Ronnie about changing your DHCP options by adding a secondary DNS server IP address to your DHCP scope options. This would allow time to transition without any DNS interruptions.