diff --git a/ci/roles/network/defaults/main.yml b/ci/roles/network/defaults/main.yml
index 095f17fa..d049736a 100644
--- a/ci/roles/network/defaults/main.yml
+++ b/ci/roles/network/defaults/main.yml
@@ -3,5 +3,5 @@ network_name_newparams: newparams_network
 network_shared: false
 network_external: false
 dns_domain: example.opendev.org
-mtu: 1350
+mtu: 1250
 port_security_enabled: false