問題文
A service is reported as unreachable from another host. The administrator wants to confirm, on the server itself, whether the process is actually accepting connections and on which address it is bound. Which observation answers this?
選択肢
- Check whether the process appears in the list of running processes, which is sufficient because a running process always has its port open.
- Read the routing table on the server, showing the paths that traffic takes and therefore which services the host answers on.
- Send a probe from the server to itself using the loopback address, because a successful reply proves that the service is reachable from the rest of the network as well, since the same process handles both cases identically.
- List the listening sockets on the host and check the local address that each one is bound to along with the port.