先看“有没有链路”，再看能不能上网

Check the link before the internet

把电脑用已知可用的网线接到墙口后，观察电脑网卡或接口灯是否出现连接状态。没有链路，通常不必先改 DNS、重装游戏或重置电脑；应优先检查这根网线、墙口另一端的跳线、以及路由器或交换机的对应端口。

Connect a computer with a known-good cable and observe whether the adapter reports a physical link. With no link, changing DNS, reinstalling software or resetting the computer is rarely the first move.

安全检查顺序

A safe check sequence

1. 01用同一根网线，先直接接到已知能用的路由器 LAN 口，确认电脑网卡和网线没有问题。
2. 02回到墙口测试，记录电脑显示“未连接”还是“已连接但无网络”。
3. 03在不拔未知电源线的前提下，查看公共配线柜或路由器旁是否有对应编号的跳线。
4. 04不要把房间墙口随机插进路由器 WAN 口；若不清楚端口用途，先拍清楚标签与现有接法。

1. 01Use the same cable directly on a known-working router LAN port to confirm the computer and cable first.
2. 02Return to the wall socket and record whether the computer shows no link or connected-without-internet.
3. 03Without unplugging unknown power equipment, look for a labelled patch lead near the router or shared distribution panel.
4. 04Do not randomly connect a room socket to a router WAN port. Photograph labels and the existing layout when unsure.

适合游戏电脑的最后一步

The final step for a gaming PC

链路出现后，再确认电脑获取到正常网络地址、能打开网页，并在稳定状态下测试。以太网可以减少无线覆盖因素，但不能自动消除服务端、路由器或局域网拥塞问题。

Once a link appears, confirm the computer obtains a normal network address and can browse before testing. Ethernet removes some WiFi variables but does not automatically eliminate service, router or local-network congestion.