diff --git a/docker-compose.dev.yml b/docker-compose.dev.yml
index 719de55..8a30288 100644
--- a/docker-compose.dev.yml
+++ b/docker-compose.dev.yml
@@ -33,6 +33,8 @@ services:
       - DATA_MANAGER_URL=htwkalender-data-manager
     networks:
       - "net"
+    depends_on:
+      - htwkalender-data-manager
 
   htwkalender-frontend:
     image: DOCKER_REGISTRY_REPO-frontend # DOCKER_REGISTRY_REPO will be replaced by CI
diff --git a/docker-compose.prod.yml b/docker-compose.prod.yml
index f52e1aa..061692b 100644
--- a/docker-compose.prod.yml
+++ b/docker-compose.prod.yml
@@ -33,6 +33,8 @@ services:
       - DATA_MANAGER_URL=htwkalender-data-manager
     networks:
       - "net"
+    depends_on:
+      - htwkalender-data-manager
 
   htwkalender-frontend:
     image: DOCKER_REGISTRY_REPO-frontend # DOCKER_REGISTRY_REPO will be replaced by CI
diff --git a/docker-compose.yml b/docker-compose.yml
index ddb62a0..01f70bb 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -35,6 +35,8 @@ services:
       target: dev  # prod
     environment:
       - DATA_MANAGER_URL=htwkalender-data-manager
+    depends_on:
+      - htwkalender-data-manager
 
   htwkalender-frontend:
     build:
diff --git a/frontend/nginx.conf b/frontend/nginx.conf
index 334df1a..dc99832 100644
--- a/frontend/nginx.conf
+++ b/frontend/nginx.conf
@@ -27,11 +27,10 @@ http {
     include       mime.types;
     default_type  application/octet-stream;
 
-    # Define a custom log format for anonymizing logs
     log_format anonymized '[$time_local] "$request" $status $body_bytes_sent "$http_referer"';
 
     access_log  /opt/bitnami/nginx/logs/proxy_access.log anonymized;
-    error_log   /opt/bitnami/nginx/logs/proxy_error.log;
+    error_log   /opt/bitnami/nginx/logs/proxy_error.log error;
 
     sendfile        on;
     keepalive_timeout  180s;
diff --git a/reverseproxy.conf b/reverseproxy.conf
index 386ab70..71332dc 100644
--- a/reverseproxy.conf
+++ b/reverseproxy.conf
@@ -59,11 +59,10 @@ http {
 
     real_ip_header CF-Connecting-IP;
 
-    # Define a custom log format for anonymizing logs
     log_format anonymized '[$time_local] "$request" $status $body_bytes_sent "$http_referer"';
 
     access_log  /opt/bitnami/nginx/logs/proxy_access.log anonymized;
-    error_log   /opt/bitnami/nginx/logs/proxy_error.log;
+    error_log   /opt/bitnami/nginx/logs/proxy_error.log error;
 
     sendfile        on;
     keepalive_timeout  180s;
diff --git a/reverseproxy.dev.conf b/reverseproxy.dev.conf
index 793ce4e..d735cad 100644
--- a/reverseproxy.dev.conf
+++ b/reverseproxy.dev.conf
@@ -60,8 +60,10 @@ http {
 
     real_ip_header CF-Connecting-IP;
 
-    access_log  /opt/bitnami/nginx/logs/proxy_access.log;
-    error_log   /opt/bitnami/nginx/logs/proxy_error.log;
+    log_format anonymized '[$time_local] "$request" $status $body_bytes_sent "$http_referer"';
+
+    access_log  /opt/bitnami/nginx/logs/proxy_access.log anonymized;
+    error_log   /opt/bitnami/nginx/logs/proxy_error.log error;
 
     sendfile        on;
     keepalive_timeout  180s;
diff --git a/reverseproxy.local.conf b/reverseproxy.local.conf
index 60b3822..42a12cf 100644
--- a/reverseproxy.local.conf
+++ b/reverseproxy.local.conf
@@ -10,6 +10,12 @@ events {
 http {
     include       mime.types;
     default_type  application/octet-stream;
+    gzip on;
+
+    log_format anonymized '[$time_local] "$request" $status $body_bytes_sent "$http_referer"';
+
+    access_log  /opt/bitnami/nginx/logs/proxy_access.log anonymized;
+    error_log   /opt/bitnami/nginx/logs/proxy_error.log error;
 
     map $request_method $ratelimit_key {
         POST     $binary_remote_addr;
diff --git a/services/data-manager/service/grpc/server.go b/services/data-manager/service/grpc/server.go
index f5b6ad3..9992ec0 100644
--- a/services/data-manager/service/grpc/server.go
+++ b/services/data-manager/service/grpc/server.go
@@ -2,8 +2,10 @@ package grpc
 
 import (
 	"github.com/pocketbase/pocketbase"
+	"google.golang.org/grpc/keepalive"
 	"log"
 	"net"
+	"time"
 
 	"google.golang.org/grpc"
 	pb "htwkalender/common/genproto/modules"
@@ -14,7 +16,20 @@ func StartGRPCServer(app *pocketbase.PocketBase) {
 	if err != nil {
 		log.Fatalf("failed to listen: %v", err)
 	}
-	s := grpc.NewServer()
+	s := grpc.NewServer(
+		grpc.KeepaliveParams(keepalive.ServerParameters{
+			MaxConnectionIdle:     5 * time.Minute,  // Idle timeout before closing connection
+			MaxConnectionAge:      30 * time.Minute, // Max time before connection is closed
+			MaxConnectionAgeGrace: 5 * time.Minute,  // Allow grace period before closing
+			Time:                  2 * time.Minute,  // Ping the client every 2 minutes
+			Timeout:               20 * time.Second, // Wait 20 seconds for ping ack
+		}),
+		grpc.KeepaliveEnforcementPolicy(keepalive.EnforcementPolicy{
+			MinTime:             1 * time.Minute, // Minimum time between pings from clients
+			PermitWithoutStream: true,            // Don't allow pings when there are no active RPCs
+		}),
+		grpc.MaxConcurrentStreams(0),
+	)
 
 	pb.RegisterModuleServiceServer(s, &ModuleServiceHandler{
 		app: app,
diff --git a/services/ical/main.go b/services/ical/main.go
index 1769786..e0a4d10 100644
--- a/services/ical/main.go
+++ b/services/ical/main.go
@@ -39,8 +39,15 @@ func main() {
 	}
 
 	grpcClient := grpc.ConnectGRPCServer(host)
+
+	// Close the grpc connection when the main function ends
 	defer grpc.CloseGRPCServer(grpcClient)
 
+	// Log the grpc connection
+	// Test the connection to the grpc server
+	grpcClient.Connect()
+	slog.Info("GRPC connection state", "state", grpcClient.GetState())
+
 	// Initialize a new Fiber app
 	webdavRequestMethods := []string{"PROPFIND", "MKCOL", "COPY", "MOVE"}
 
diff --git a/services/ical/model/eventModel.go b/services/ical/model/eventModel.go
index 2d92a0d..511ad22 100644
--- a/services/ical/model/eventModel.go
+++ b/services/ical/model/eventModel.go
@@ -37,6 +37,14 @@ func (events Events) Sort() {
 	})
 }
 
+func (events Events) String() string {
+	var str strings.Builder
+	for _, event := range events {
+		str.WriteString(event.String())
+	}
+	return str.String()
+}
+
 type AnonymizedEventDTO struct {
 	Day   string   `db:"Day" json:"day"`
 	Week  string   `db:"Week" json:"week"`
@@ -109,3 +117,7 @@ func (e *Event) GetName() string {
 func (e *Event) SetName(name string) {
 	e.Name = name
 }
+
+func (e *Event) String() string {
+	return e.UUID + e.Day + e.Week + e.Start.String() + e.End.String() + e.Name + e.EventType + e.Compulsory + e.Prof + e.Rooms + e.Notes + e.BookedAt + e.Course + e.Semester
+}
diff --git a/services/ical/model/icalModel.go b/services/ical/model/icalModel.go
index 14121fd..e5cab49 100644
--- a/services/ical/model/icalModel.go
+++ b/services/ical/model/icalModel.go
@@ -92,3 +92,7 @@ func ToJSONTime(timeString string) JSONTime {
 	}
 	return JSONTime(t)
 }
+
+func (j JSONTime) String() string {
+	return time.Time(j).Format(DefaultDateLayout)
+}
diff --git a/services/ical/service/connector/grpc/client.go b/services/ical/service/connector/grpc/client.go
index 7b3b261..1954523 100644
--- a/services/ical/service/connector/grpc/client.go
+++ b/services/ical/service/connector/grpc/client.go
@@ -19,14 +19,31 @@ package grpc
 import (
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/keepalive"
 	"log/slog"
+	"sync"
+	"time"
 )
 
+var conn *grpc.ClientConn
+var once sync.Once
+
 func ConnectGRPCServer(host string) *grpc.ClientConn {
-	conn, err := grpc.NewClient(host+":50051", grpc.WithTransportCredentials(insecure.NewCredentials()))
-	if err != nil {
-		slog.Error("could not connect to grpc server", "error", err)
-	}
+	once.Do(func() {
+		var err error
+		conn, err = grpc.NewClient(
+			host+":50051",
+			grpc.WithTransportCredentials(insecure.NewCredentials()),
+			grpc.WithKeepaliveParams(keepalive.ClientParameters{
+				Time:                2 * time.Minute,
+				Timeout:             20 * time.Second,
+				PermitWithoutStream: true,
+			}),
+		)
+		if err != nil {
+			slog.Error("could not connect to grpc server", "error", err)
+		}
+	})
 	return conn
 }
 
diff --git a/services/ical/service/ical/ical.go b/services/ical/service/ical/ical.go
index ba8e7f2..11759e0 100644
--- a/services/ical/service/ical/ical.go
+++ b/services/ical/service/ical/ical.go
@@ -23,6 +23,7 @@ import (
 	"htwkalender/ical/model"
 	"htwkalender/ical/service/connector"
 	htwkalenderGrpc "htwkalender/ical/service/connector/grpc"
+	"htwkalender/ical/service/functions"
 	"log/slog"
 	"time"
 )
@@ -31,7 +32,7 @@ const expirationTime = 5 * time.Minute
 
 var FeedDeletedError = fmt.Errorf("feed deleted")
 
-func Feed(app model.AppType, token string) (string, error) {
+func Feed(app model.AppType, token string) (string, string, error) {
 
 	var events model.Events
 	modules := map[string]model.FeedCollection{}
@@ -47,17 +48,17 @@ func Feed(app model.AppType, token string) (string, error) {
 		// get feed by token
 		feed, err := htwkalenderGrpc.GetFeed(token, app.GrpcClient)
 		if err != nil {
-			return "", err
+			return "", "", err
 		}
 
 		if feed.Deleted {
-			return "", FeedDeletedError
+			return "", "", FeedDeletedError
 		}
 
 		// Get all events for modules
 		events, err = htwkalenderGrpc.GetEvents(feed.Modules, app.GrpcClient)
 		if err != nil {
-			return "", err
+			return "", "", err
 		}
 
 		// Sort events by start date
@@ -68,11 +69,14 @@ func Feed(app model.AppType, token string) (string, error) {
 		}
 	}
 
+	// Generate one Hash for E-TAG from all events and modules
+	etag := functions.HashString(events.String() + fmt.Sprint(modules))
+
 	b := bytes.Buffer{}
 	goics.NewICalEncode(&b).Encode(IcalModel{Events: events, Mapping: modules})
 	icalFeed := &model.FeedModel{Content: b.String(), ExpiresAt: model.JSONTime(time.Now().Add(expirationTime))}
 
-	return icalFeed.Content, nil
+	return icalFeed.Content, etag, nil
 }
 
 func FeedRecord(app model.AppType, token string) (model.FeedRecord, error) {
diff --git a/services/ical/service/routes.go b/services/ical/service/routes.go
index c92a0f7..f7da962 100644
--- a/services/ical/service/routes.go
+++ b/services/ical/service/routes.go
@@ -34,7 +34,8 @@ func AddFeedRoutes(app model.AppType) {
 	app.Fiber.Get("/api/feed", func(c fiber.Ctx) error {
 
 		token := c.Query("token")
-		results, err := ical.Feed(app, token)
+		ifNoneMatch := c.Get("If-None-Match")
+		results, eTag, err := ical.Feed(app, token)
 
 		if errors.Is(err, ical.FeedDeletedError) {
 			return c.SendStatus(fiber.StatusGone)
@@ -44,10 +45,16 @@ func AddFeedRoutes(app model.AppType) {
 			slog.Error("Failed to get feed", "error", err, "token", token)
 			return c.SendStatus(fiber.StatusNotFound)
 		}
+
+		if ifNoneMatch == eTag && ifNoneMatch != "" {
+			return c.SendStatus(fiber.StatusNotModified)
+		}
+
 		c.Response().Header.Set("Content-type", "text/calendar")
 		c.Response().Header.Set("charset", "utf-8")
 		c.Response().Header.Set("Content-Disposition", "inline")
 		c.Response().Header.Set("filename", "calendar.ics")
+		c.Response().Header.Set("ETag", eTag)
 
 		return c.SendString(results)
 	})