unable to ping from one vagrant vm to another in osx virtualbox

[Tony Wong]

I deployed 3 centos VMs on virtualbox running in osx

I used bridge mode on all 3 vms. 

I see I have both a nat adapter and a bridge adapter

all 3 vms can ping internet

but they are unable to ping each other

any idea?

from my osx host I can ping all 3 vms by their bridge ip