diff --git a/tun_linux.go b/tun_linux.go
index cf66a8c..6a9cb09 100644
--- a/tun_linux.go
+++ b/tun_linux.go
@@ -216,6 +216,7 @@ func (c Tun) Activate() error {
 		LinkIndex: link.Attrs().Index,
 		Dst:       dr,
 		MTU:       c.DefaultMTU,
+		AdvMSS:    c.advMSS(route{}),
 		Scope:     unix.RT_SCOPE_LINK,
 		Src:       c.Cidr.IP,
 		Protocol:  unix.RTPROT_KERNEL,
@@ -233,6 +234,7 @@ func (c Tun) Activate() error {
 			LinkIndex: link.Attrs().Index,
 			Dst:       r.route,
 			MTU:       r.mtu,
+			AdvMSS:    c.advMSS(r),
 			Scope:     unix.RT_SCOPE_LINK,
 		}
 
@@ -248,6 +250,7 @@ func (c Tun) Activate() error {
 			LinkIndex: link.Attrs().Index,
 			Dst:       r.route,
 			MTU:       r.mtu,
+			AdvMSS:    c.advMSS(r),
 			Scope:     unix.RT_SCOPE_LINK,
 		}
 
@@ -265,3 +268,16 @@ func (c Tun) Activate() error {
 
 	return nil
 }
+
+func (c Tun) advMSS(r route) int {
+	mtu := r.mtu
+	if r.mtu == 0 {
+		mtu = c.DefaultMTU
+	}
+
+	// We only need to set advmss if the route MTU does not match the device MTU
+	if mtu != c.MaxMTU {
+		return mtu - 40
+	}
+	return 0
+}
diff --git a/tun_linux_test.go b/tun_linux_test.go
new file mode 100644
index 0000000..4e70aa0
--- /dev/null
+++ b/tun_linux_test.go
@@ -0,0 +1,31 @@
+package nebula
+
+import "testing"
+
+var runAdvMSSTests = []struct {
+	name     string
+	tun      Tun
+	r        route
+	expected int
+}{
+	// Standard case, default MTU is the device max MTU
+	{"default", Tun{DefaultMTU: 1440, MaxMTU: 1440}, route{}, 0},
+	{"default-min", Tun{DefaultMTU: 1440, MaxMTU: 1440}, route{mtu: 1440}, 0},
+	{"default-low", Tun{DefaultMTU: 1440, MaxMTU: 1440}, route{mtu: 1200}, 1160},
+
+	// Case where we have a route MTU set higher than the default
+	{"route", Tun{DefaultMTU: 1440, MaxMTU: 8941}, route{}, 1400},
+	{"route-min", Tun{DefaultMTU: 1440, MaxMTU: 8941}, route{mtu: 1440}, 1400},
+	{"route-high", Tun{DefaultMTU: 1440, MaxMTU: 8941}, route{mtu: 8941}, 0},
+}
+
+func TestTunAdvMSS(t *testing.T) {
+	for _, tt := range runAdvMSSTests {
+		t.Run(tt.name, func(t *testing.T) {
+			o := tt.tun.advMSS(tt.r)
+			if o != tt.expected {
+				t.Errorf("got %d, want %d", o, tt.expected)
+			}
+		})
+	}
+}