If no inbound traffic appears, it may be that the host isn't responding or there's no valid route from your host to the target or vice versa.

如果没有出现入站通信流，可能是主机没有响应，或者在您的主机和目标主机之间没有有效的路由。

youdao

If a valid route exists to the host, and it's responding to pings but the application service is failing to respond, then you can check connectivity to the relevant ports using Telnet.

如果存在到主机的有效路由，而且它能够响应ping，但是应用服务没有响应，那么可以使用telnet检查到相关端口的连接。

youdao

Use traceroute (see Listing 9) to trace the full route to and from the target host.

使用traceroute(见清单9)跟踪到目标主机和来自目标主机的完整路由。

youdao

The baton will then make its journey from Delhi - which was the host of the 2010 Games - along a route detailed in the map above.

BBC: Scotland

Even with his wimpy DSL connection, pages are rendered quickly enough once the website's servers (and all the other computers along the route, plus those used to host adverts, graphics and miscellaneous layout bits) start giving his browser's request some attention.

ECONOMIST: The faster the internet becomes, the slower it loads pages