Project Name

GetPathMTU is a bash script that provides the user a way to test the maximum supported MTU between the source where code is executed and the destination provided.

Clone the repository or download GetPathMTU.sh directly, then run the script.

1. Clone the Repository

   git clone https://github.com/Azure-Samples/GetPathMTU.git

2. Navigate into the folder containing the script

   cd GetPathMTU

3. Run the script

   ./GetPathMTU.sh <Destination IP>

Destination IPv4-Address : This is mandatory parameter, we can either use the parameter with a flat -s or without a flag Initial Buffer size : This optional parameter, the default value is 1200 bytes Interface Name : This optional parameter, not using the inteface parameter will use the default interface for communication

./GetPathMtu.sh  10.1.0.4  
./GetPathMtu.sh  -r 10.1.0.4 -l 2100 -i eth0
./GetPathMtu.sh  -r 10.1.0.4 -l 1000
./GetPathMtu.sh  -r <destination-ip> -l <initial-packet-size> -i <interface-name>
./GetPathMtu.sh  -r  10.1.0.4 -l 1200 -i eth0

Sample results:

$ ./GetPathMtu.sh 10.1.0.4
destination: 10.1.0.4
startSendBufferSize: 1200
interfaceName: Default interface
Test started .....................................
1492

In this instance 1492 is the maximum MTU size (IP Header + Payload) allowable from the source running the script to the destination.

The Powershell Test-Connection command provides similiar capability with -MtuSize parameter.