DNS issues on ovelapping site-to-site VPN

RouterOS General
1

I have done a site-to-site VPN of an overlapping network between 2 sites; our offices and a company that we acquired. We are using 2 RB1100AHx2 using netmap on the other side and it is working well.

However I’ve hit a stumbling block. The problem is that I would like to get the DNS server from the other company to forward records to my company, but I would like the IP address to be received translated.

For example, imagine I have an IP scheme of 192.168.0.0/16 at my company, and 192.168.100.0/24 at the other company. Using Netmap I create mappings from 172.16.0.0/24 to 192.168.100.0/24 and perform site-to-site VPN between 192.168.0.0/16 and 172.16.0.0/24. If I have a DNS server at the other site with IP address of 192.168.100.100, its translated address would be 172.16.0.100, that is fine. But the addresses it contains would still be on the 192.168.100.0/24 range. How shall I get DNS records from such DNS server to my company in the 172.16.0.0/24 range so that I can ping them perfectly from our offices?

Thanks,
Vince

2

I can imagine some DNS mangling proxy, but I’m not sure if such thing exists and even if it does, it’s definitely not included in RouterOS.

Another way could be if your DNS server supports split horizon, i.e. giving one record to clients from one address range and different record to other clients. You could configure it to give 192.168.x.y addresses to local clients and 172.16.x.y addresses to remote clients. This is possible for sure, not necessarily with your DNS server, but with some yes.