Split horizon is the ability for a DNS-server to give a different answer to a query based on the source of the query. A common use-case is when using the same DNS-server for internal and external queries. When your DNS is publicly available, you really don’t want to enable recursion to the outside world but internally it could be handy. Besides security there are also examples where resolving a certain name needs to return an internal IP while externally that IP is useless and it’s better to return something else.
DNS or Domain Name System is one of the most important building blocks of the modern IT and internet. DNS allows you to use meaningful names instead of IP addresses. Especially since IPv6 is getting more popular, DNS remains a very important part of your network. This article will describe how to set up a basic master DNS-server and a slave which will replicate the data from the master.