# tunnel mtu

#### Syntax

tunnel mtu mtuSize

no tunnel mtu

#### Release Information

Command introduced before JunosE Release 7.1.0
IPSec Tunnel Profile Configuration mode added in JunosE Release 7.3.0.
IP Tunnel Destination Profile Configuration mode added in JunosE Release 8.2.0.

#### Description

Configures the maximum transmission unit size for the particular tunnel. The no version restores the default value, 1024 for static DVMRP and GRE tunnels, 10240 for dynamic DVMRP and GRE tunnels, 1440 for static IPSec tunnels, and 1400 for dynamic IPSec tunnels.

#### Options

- mtuSize—Packet size in bytes allowed for transmission through the tunnel in the range; in the range 1024–10240 for DVMRP and GRE tunnels, in the range 160–9000 for IPSec tunnels.

#### Mode

Interface Configuration, IP Tunnel Destination Profile Configuration, IPSec Tunnel Profile Configuration