mtuprobe

A tool to probe the current MTU on an IPv4 path.

So far it's compatible with Linux only however it can very easily be adapted to any other operating system.

Installation

pip install mtuprobe

Usage

The default options are sane and should give you good results. Suppose that you want to know the current effective MTU towards wikipedia.org, in a shell you can try:

% mtuprobe wikipedia.org
Max packet size:         1464
Expected ethernet MTU:   1492

You can check out mtuprobe -h to get the complete list of options.

Values are:

• Max packet size — Max packet size specified to ping, meaning the size of the data segment of the ICMP packet
• Expected ethernet MTU — That's what the MTU should be if you're transmitting over Ethernet and the header sizes are what is expected from such a setup. This should apply most of the time but surely some weird network setups could violate this.