diff --git a/linux/system/single.yml b/linux/system/single.yml
index fcfa1b1..44bfbfd 100644
--- a/linux/system/single.yml
+++ b/linux/system/single.yml
@@ -12,6 +12,8 @@
         cloud-init:
           version: purged
       kernel:
+        modules:
+          - nf_conntrack
         sysctl:
           net.ipv4.tcp_keepalive_intvl: 3
           net.ipv4.tcp_keepalive_time: 30