diff --git a/respond/daemon/config.go b/respond/daemon/config.go
index 9bff26e..ebfd0e8 100644
--- a/respond/daemon/config.go
+++ b/respond/daemon/config.go
@@ -3,6 +3,7 @@ package respondd
 import (
 	"io/ioutil"
 	"strings"
+	"sync"
 
 	"github.com/FreifunkBremen/yanic/data"
 	"github.com/FreifunkBremen/yanic/lib/duration"
@@ -26,6 +27,7 @@ type Daemon struct {
 	Babel     string                 `toml:"babel"`
 	babelData *babelState.BabelState `toml:"-"`
 
+	dataMX          sync.Mutex
 	dataByInterface map[string]*data.ResponseData
 
 	Answer        *AnswerConfig            `toml:"defaults"`
diff --git a/respond/daemon/data.go b/respond/daemon/data.go
index 51b1ef3..839bf01 100644
--- a/respond/daemon/data.go
+++ b/respond/daemon/data.go
@@ -22,6 +22,8 @@ func (d *Daemon) updateData() {
 }
 
 func (d *Daemon) getData(iface string) *data.ResponseData {
+	d.dataMX.Lock()
+	defer d.dataMX.Unlock()
 	if iData, ok := d.dataByInterface[iface]; ok {
 		return iData
 	}
diff --git a/respond/daemon/main.go b/respond/daemon/main.go
index ac25176..10c9f57 100644
--- a/respond/daemon/main.go
+++ b/respond/daemon/main.go
@@ -16,7 +16,9 @@ func (d *Daemon) Start() {
 		d.AnswerByZones = make(map[string]*AnswerConfig)
 	}
 
+	d.dataMX.Lock()
 	d.updateData()
+	d.dataMX.Unlock()
 	go d.updateWorker()
 
 	if d.Babel != "" {
@@ -69,6 +71,8 @@ func (d *Daemon) updateWorker() {
 	c := time.Tick(d.DataInterval.Duration)
 
 	for range c {
+		d.dataMX.Lock()
 		d.updateData()
+		d.dataMX.Unlock()
 	}
 }