diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index fcec5090f3083ad5cdefa94d0022a19fce321d5e..9b53c88c892567f8db11f430a01477bb0314f501 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -10,6 +10,8 @@ variables:
   IMAGE_TAG: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_NAME
   DOCKER_HOST: tcp://docker:2375
   DOCKER_TLS_CERTDIR: ""
+  # MTU 1400 for hetzner vSwitch
+  DOCKER_OPTS: "--mtu=1400"
 
 cache:
   key: ${CI_PROJECT_ID}