Bug ID 843597: Ensure the system does not set the VE's MTU higher than the vmxnet3 driver can handle

Last Modified: Sep 13, 2023

Affected Product(s):
BIG-IP All(all modules)

Known Affected Versions:
13.1.3,,,,,,, 14.0.1,,, 14.1.2,,,,,,,,, 14.1.3, 15.0.0, 15.0.1,,,,, 15.1.0,,,,,, 15.1.1

Fixed In:
16.0.0, 15.1.2,,

Opened: Oct 28, 2019

Severity: 3-Major


The vmxnet3 driver cannot handle MTUs larger than 9000 bytes. This issue can present itself in a few different ways, depending on the underlying platform. One example would be the BIG-IP failing to initialize vmxnet interfaces with messages similar to the following logged in /var/log/tmm: notice vmxnet3[1b:00.0]: MTU: 9198 notice vmxnet3[1b:00.0]: Error: Activation command failed: 1 If the BIG-IP does successfully initialize its vmxnet interfaces, there can be unpredictable behavior (possibly with the hypervisor).


The BIG-IP system may not be able to initialize the vmxnet3 interfaces on startup. If it is able to do so, then packets may be dropped, or the hypervisor may crash on some platforms that do not handle this condition gracefully.


-- Using a BIG-IP Virtual Edition (VE) with the vmxnet3 driver. -- If the BIG-IP is able to initialize the vmxnet interfaces: Passing packets larger than 9000 bytes.


Modify the tmm_init.tcl file, adding the following line: ndal mtu 9000 15ad:07b0

Fix Information

The software now ensure that the default setting for the vmxnet3 driver MTU is 9000, which prevents the issue from occurring.

Behavior Change

Guides & references

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