I am facing some strange packet drop issue here. scenario as below:
Router A ---WAN CONNECTION--- Router B
a. Router A ping to Router B, no packet drop.
b. Router B ping to Router A, no packet drop.
c. Router B ping it's own WAN ip address, no packet drop.
d. Router A ping it's own WAN ip address, observe packet drop.
e. No QoS setting at both end.
What could be the reason cause this problem?
Thank you for your help!