This is certainly not the only case of &quot;network subtly broken on cloud VMs&quot;. For example, every provider I have tested (including AWS, Rackspace, Digital Ocean, Linode) enables TCP segment reassembly offload, and provides no way to disable it (presumably because it is being done on the host not the VM). This will typically break TCP tunneling (e.g. using GRE) because PMTUD doesn&#x27;t work under these conditions. fwiw a shout out to Soft Layer which is the only VM hosting provider I&#x27;m aware of that does not suffer from this blight (provided you pay for additional IP addresses routed to your box).