How to check MTU value in AIX

In Short

    • netstat -in
    • lsattr -El en0 | grep mtu

Both netstat and lsattr can be used to display the mtu size of an interface in AIX partition

Detailed Explanation

MTU Size is the largest packet size that can be transferred from one node to another connected node. Node is networking terminology that refers to AIX partition. 1500 packet size is not mandatory there may be lesser than 1500 packets length also getting transferred in network but 1500 is the standard mtu size.

There are two ways to find out the mtu size in network

Method 1

    • netstat -in     (or)    netstat -I interface

Netstat is a program that displays the network statistics of all the network interfaces that present in AIX partition. It will not only display the mtu size but also the number of packets in and out and number of error occurred the transmission. 

netstat -I en0
Name   Mtu   Network     Address                 Ipkts     Ierrs        Opkts     Oerrs  Time
en0    1500  link#4      mac_address                1686875725     0        166648516     3     0
en0    1500  9.x.x.y     partition1                 1686875725     0        166648516     3     0

Method 2
    • lsattr -El interface | grep mtu
lsattr is the standard utility that is provided in AIX to display all the attributes associated with devices. As mtu is one of the attribute of network lsattr can be used to display the attributes.

lsattr -El en0 | grep mtu
mtu           1500          Maximum IP Packet Size for This Device        True

With these two commands we will be able to find out the Network Packet Size for that network adapter and interface.