One office originally uses X company? products for networking. During service capacity expansion, the NE16E is used to replace the original routers. After service cutover, most services are found normal except for those connected to one FE port.
Enable the arp proxy on the FE port, or change the next hop of the static route on the peer equipment to the IP address of the FE port instead of the FE egress.
The most possible reason for service failed on a FE port is port fault. However, when a PC is directly connected to the FE port on site, everything is OK. Therefore, there may be some trouble with the equipment connected to the NE16E. After checking the configuration of the connected equipment, it is found that the equipment uses static route and the next hop of the uplink route information is the local FE interface. The problem is cleared after you change the next hop of the route information to the interface port of the NE16E.
Why the original equipment has no problem? After careful analysis, it is known that the FE port of the original router defaults to start the arp proxy and uses the MAC address of the FE interface to respond to the arp requests for the destination network segment sent from the downlink equipment. Therefore, it provides the same function as the downlink equipment configures the next hop of the route information as the interface address of the uplink equipment. The NE16E also supports the arp proxy function, but defaults to disable it on the port. Therefore, the above problem occurs.