}
	// sanitize the server hosts as it could contain hosts of form ns/host
	sniHosts := sets.String{}
	for _, h := range server.Hosts {
		if strings.Contains(h, "/") {
			parts := strings.Split(h, "/")
			h = parts[1]
		}
		// do not add hosts, that have already been added
		sniHosts.Insert(h)
	}
	return sets.SortedList(sniHosts)
}

// CheckDuplicates returns all of the hosts provided that are already known