diff --git a/constants/consts.go b/constants/consts.go
index 50bef029..aef34655 100755
--- a/constants/consts.go
+++ b/constants/consts.go
@@ -24,6 +24,7 @@ const (
 	RoleListFile        = "../RoleList.dat"
 	VoteFile            = "votes.dat"
 	MembersPrefix       = "M"
+	PrivatePrefix       = "P"
 	RegularsPrefix      = "R"
 	ArchiveFolderSuffix = " maps"
 	TempSaveName        = "softmod.tmp"
diff --git a/fact/factConfGen.go b/fact/factConfGen.go
index d8117b80..85ff22d1 100755
--- a/fact/factConfGen.go
+++ b/fact/factConfGen.go
@@ -57,7 +57,9 @@ func GenerateFactorioConfig() bool {
 		constants.ServSettingsName
 
 	var servName string
-	if cfg.Local.Options.MembersOnly || cfg.Local.Options.RegularsOnly {
+	if cfg.Local.Options.CustomWhitelist {
+		cfg.ServerPrefix = constants.PrivatePrefix
+	} else if cfg.Local.Options.MembersOnly || cfg.Local.Options.RegularsOnly {
 		if cfg.Local.Options.RegularsOnly {
 			cfg.ServerPrefix = constants.RegularsPrefix
 		} else {