diff --git a/src/config.rs b/src/config.rs
index c3a7c2c..8173b7e 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -23,6 +23,7 @@ pub struct Config {
     pub device_type: Type,
     pub device_name: String,
     pub device_path: Option<String>,
+    pub device_mtu: Option<usize>,
     pub fix_rp_filter: bool,
 
     pub ip: Option<String>,
@@ -61,6 +62,7 @@ impl Default for Config {
             device_type: Type::Tun,
             device_name: "vpncloud%d".to_string(),
             device_path: None,
+            device_mtu: None,
             fix_rp_filter: false,
             ip: None,
             ifup: None,
@@ -105,6 +107,9 @@ impl Config {
             if let Some(val) = device.path {
                 self.device_path = Some(val);
             }
+            if let Some(val) = device.mtu {
+                self.device_mtu = Some(val);
+            }
             if let Some(val) = device.fix_rp_filter {
                 self.fix_rp_filter = val;
             }
@@ -210,6 +215,9 @@ impl Config {
         if let Some(val) = args.device_path {
             self.device_path = Some(val);
         }
+        if let Some(val) = args.device_mtu {
+            self.device_mtu = Some(val);
+        }
         if args.fix_rp_filter {
             self.fix_rp_filter = true;
         }
@@ -316,6 +324,7 @@ impl Config {
             device: Some(ConfigFileDevice {
                 name: Some(self.device_name),
                 path: self.device_path,
+                mtu: self.device_mtu,
                 type_: Some(self.device_type),
                 fix_rp_filter: Some(self.fix_rp_filter)
             }),
@@ -417,6 +426,10 @@ pub struct Args {
     #[structopt(long)]
     pub device_path: Option<String>,
 
+    /// Set the mtu og the device
+    #[structopt(long)]
+    pub device_mtu: Option<usize>,
+
     /// Fix the rp_filter settings on the host
     #[structopt(long)]
     pub fix_rp_filter: bool,
@@ -619,6 +632,7 @@ pub struct ConfigFileDevice {
     pub type_: Option<Type>,
     pub name: Option<String>,
     pub path: Option<String>,
+    pub mtu: Option<usize>,
     pub fix_rp_filter: Option<bool>,
 }
 
@@ -675,6 +689,7 @@ device:
   type: tun
   name: vpncloud%d
   path: /dev/net/tun
+  mtu: 1400
 ip: 10.0.1.1/16
 ifup: ifconfig $IFNAME 10.0.1.1/16 mtu 1400 up
 ifdown: 'true'
@@ -708,6 +723,7 @@ statsd:
                 type_: Some(Type::Tun),
                 name: Some("vpncloud%d".to_string()),
                 path: Some("/dev/net/tun".to_string()),
+                mtu: Some(1400),
                 fix_rp_filter: None
             }),
             ip: Some("10.0.1.1/16".to_string()),
@@ -756,6 +772,7 @@ async fn config_merge() {
             type_: Some(Type::Tun),
             name: Some("vpncloud%d".to_string()),
             path: None,
+            mtu: None,
             fix_rp_filter: None,
         }),
         ip: None,
@@ -847,6 +864,7 @@ async fn config_merge() {
         device_type: Type::Tap,
         device_name: "vpncloud0".to_string(),
         device_path: Some("/dev/null".to_string()),
+        device_mtu: None,
         fix_rp_filter: false,
         ip: None,
         ifup: Some("ifconfig $IFNAME 10.0.1.2/16 mtu 1400 up".to_string()),
diff --git a/src/main.rs b/src/main.rs
index b298930..745a5ba 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -144,8 +144,8 @@ async fn setup_device(config: &Config) -> TunTapDevice {
     );
     info!("Opened device {}", device.ifname());
     config.call_hook("device_setup", vec![("IFNAME", device.ifname())], true);
-    if let Err(err) = device.set_mtu(None).await {
-        error!("Error setting optimal MTU on {}: {}", device.ifname(), err);
+    if let Err(err) = device.set_mtu(config.device_mtu).await {
+        error!("Error setting MTU on {}: {}", device.ifname(), err);
     }
     if let Some(ip) = &config.ip {
         let (ip, netmask) = try_fail!(parse_ip_netmask(ip), "Invalid ip address given: {}");
diff --git a/src/oldconfig.rs b/src/oldconfig.rs
index 30db169..70fe744 100644
--- a/src/oldconfig.rs
+++ b/src/oldconfig.rs
@@ -103,6 +103,7 @@ impl OldConfigFile {
                 fix_rp_filter: None,
                 name: self.device_name,
                 path: self.device_path,
+                mtu: None,
                 type_: self.device_type
             }),
             group: self.group,