Specifies the other DHCP server to load data from. This is a new feature in V2.9 and allows to setup redundant configurations for DNS. The idea is when you setup the split scope redundancy, as described in the FAQ, then you need to handle local DNS requests. See the FAQ for more information.
[Settings] SyncServer=other-server:80 ; load data from other-server
In order for this to work you need to configure the HTTP function on the other server. IP addresses or names are allowed optionally followed by a colon and the port number of the server.