Avoid jumbo frames as it produces issues with traffic flow.

pkg/netconf/interfaces_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"sort"
+	"strings"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -70,8 +71,8 @@ func equalDirs(dir1, dir2 string) (bool, string) {
 		if err != nil {
 			panic(err)
 		}
-		s1 := string(f1)
-		s2 := string(f2)
+		s1 := strings.TrimSpace(string(f1))
+		s2 := strings.TrimSpace(string(f2))
 		if !cmp.Equal(s1, s2) {
 			return false, fmt.Sprintf("file %s differs: %v", f, cmp.Diff(s1, s2))
 		}

pkg/netconf/systemd.go

@@ -15,9 +15,9 @@ const (
 	// tplSystemdNetworkLan defines the name of the template to render system.network file.
 	tplSystemdNetworkLan = "networkd/10-lan.network.tpl"
 	// mtuFirewall defines the value for MTU specific to the needs of a firewall. VXLAN requires higher MTU.
-	mtuFirewall = 9216
+	mtuFirewall = 1500
 	// mtuMachine defines the value for MTU specific to the needs of a machine.
-	mtuMachine = 9000
+	mtuMachine = 1440
 )
 
 type (

pkg/netconf/testdata/networkd/firewall/10-lan0.link

@@ -6,4 +6,4 @@ PermanentMACAddress=00:03:00:11:11:01
 [Link]
 Name=lan0
 NamePolicy=
-MTUBytes=9216
+MTUBytes=1500

pkg/netconf/testdata/networkd/firewall/11-lan1.link

@@ -6,4 +6,4 @@ PermanentMACAddress=00:03:00:11:12:01
 [Link]
 Name=lan1
 NamePolicy=
-MTUBytes=9216
+MTUBytes=1500

pkg/netconf/testdata/networkd/machine/10-lan0.link

@@ -6,4 +6,4 @@ PermanentMACAddress=00:03:00:11:11:01
 [Link]
 Name=lan0
 NamePolicy=
-MTUBytes=9000
+MTUBytes=1440

pkg/netconf/testdata/networkd/machine/11-lan1.link

@@ -6,4 +6,4 @@ PermanentMACAddress=00:03:00:11:12:01
 [Link]
 Name=lan1
 NamePolicy=
-MTUBytes=9000
+MTUBytes=1440