The MA5200F connects to a router and the router can ping the MA5200F successfully, but the MA5200F cannot.
There are two methods to solve the problem.
1) Set the lookback0 address of the MA5200F to the same network segment as the downstream IP address of the router.
2) Specify a source address in the ping command and the address specified must be the address of some interface of the MA5200F. Here it is configured to the upstream port IP address of the MA5200F.
-a specifies the source address in the ping command. MA5200: The CAR Attribute Issued by No. 26 Attribute Cannot Be Translated Due to RADIUS Server Connection
No ACL is configured on either end. It does not work to change the ports or replace the two ends with two PCs. Execute packet capture on the two ends and find that the source address of the sent-out packet is the lookback0 address.
The router can ping the MA5200F successfully because the downstream IP address of the router is in the same network segment as the upstream IP address of the MA5200F. The MA5200F is configured with a lookback0 address. So the source address defaults to the lookback0 address when no source address is specified in the ping command. In case the lookbac0k address is not in the same network segment as the downstream IP address of the router and there is no static route configured on the router to the loopback address, the MA5200F cannot ping the router accordingly.