diff --git a/Dockerfile b/Dockerfile
index b239585..6151471 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,7 @@
 FROM golang:1.22-alpine AS build
 WORKDIR /src
 COPY go.mod ./
+COPY go.sum ./
 RUN go mod download
 COPY main.go ./
 RUN CGO_ENABLED=0 go build -trimpath -ldflags="-s -w" -o /out/asn-header-service
@@ -13,4 +14,3 @@ COPY --from=build /out/asn-header-service /app/asn-header-service
 EXPOSE 8080
 ENV ADDR=:8080
 ENTRYPOINT ["/app/asn-header-service"]
-