Topology: public network－－－NE80���convergence switch���campus network (server)
NAT address pool: ×.×.146.160～×.×.146.165
The public network address mapping is enabled on NE80 and the campus network is enabled on NE40 or AR4640, server private network address.
The server of campus network cannot connect with public network.
One static blackhole route to address pool has been configured ip route ×.×.146.0 255.255.255.0 null0.
In order that external Ethernet interface of the router can reply ARP request, it is required to configure on NE80 upstream interface: nat match-host pool-name. And then the service connection is realized.
Check the configuration and it is found that NE80 upstream interface address ×.×.146.158 and IP of address pool are in the same network segment. The address of address pool and external Ethernet interface address are in the same network segment; after external Ethernet interface receives ARP request packets, it finds destination address is not itself and it does not reply ARP request.
The address pool and upstream interface IP are in the same network segment and upstream interface type is broadcast network such as Ethernet and it should add configurtion under upstream interface mode: nat match-host pool-name.