On Fri, 20 May 2016, Jonathan Morton wrote:

>> On 20 May, 2016, at 20:01, Rick Jones <rick.jones2@hpe.com> wrote:
>>
>> But I haven't seen that EMSGSIZE happen with netperf UDP tests - could be though I've never run them in an environment which triggered PTMUD.
>
> It’s entirely possible that netperf and/or iperf3 are (ab)using the IP_MTU_DISCOVERY socket option mentioned.

iperf3 defaults to a mss of 1200 bytes, well below the MTU

David Lang