Networking Intermediate

What is MTU (Maximum Transmission Unit)?

The maximum size of a data packet that can be transmitted over a network without fragmentation.

MTU defines the largest packet size a network link can handle. Standard Ethernet MTU is 1500 bytes. Packets larger than MTU are either fragmented (split into smaller packets) or dropped if the Don't Fragment flag is set.

MTU mismatches cause connectivity issues — packets are silently dropped. Path MTU Discovery automatically finds the smallest MTU along a route. Jumbo frames (MTU 9000) improve performance on local networks. VPN and tunnel overhead may require reducing MTU.

Related Terms

A protocol that automatically assigns IP addresses and network configuration to devices on a network.

A network security system that monitors and controls incoming and outgoing traffic based on predetermined rules.

NAT (Network Address Translation)

A method of mapping private IP addresses to public IP addresses, allowing multiple devices to share a single public IP.

Overlay Network

A virtual network built on top of an existing physical network, enabling features like container networking and VPNs.

ICMP (Internet Control Message Protocol)

A network protocol used for diagnostic and error reporting, including ping and traceroute functionality.

A compact method for specifying IP addresses and their associated routing prefix using a slash followed by the prefix length.

View All Networking Terms →