Waterloo: After the Power Cable Was Knocked Out, a Telstra DSL Line Came Back with a Red Light, WiFi but No Internet

Waterloo：电源线被碰掉后，Telstra DSL 恢复成红灯——有 WiFi 却没有网络

Returning client · Waterloo老客户返场 · WaterlooTelstra 100M DSLTelstra 100兆 DSLASUS routerASUS 路由器Red indicator light指示灯红色WiFi but no internet有WiFi没网络Reset + provider refresh重置 + 运营商刷新

A returning client in Waterloo — we had installed their router back in April. They knocked the power cable out, plugged it back in, and the router came up with a red indicator: devices could still join the WiFi, but nothing would load. Most routers recover a line on their own once power returns. When one does not, it is worth knowing what the realistic causes are before you buy a replacement.

Waterloo 的一位老朋友返场——四月份帮他上门装的路由器。他不小心把电源线碰掉了，重新插上后路由器亮起红灯：设备照样能连上 WiFi，但什么都打不开。绝大部分路由器在恢复供电后会自己把线路接回来。如果没有接回来，在你去买新机之前，值得先搞清楚现实中有哪几种可能。

Where the chain broke · WiFi was never the problem链路断在哪 · 问题从来不是 WiFi

Telstra DSL lineTelstra DSL 电话线

100M

→

ASUS router WANASUS 路由器 WAN

red

Bottleneck瓶颈

→

Router WiFi radio路由器 WiFi 信号

→

Your devices你的设备

no internet

This is the classic shape of a WiFi-but-no-internet fault. The wireless radio inside the router comes back up on its own after a power cut, so phones and laptops still see the network and still get a local IP. What did not come back was the WAN side — the router never re-established the line with Telstra, which is what the red indicator was telling us.这是「有 WiFi 但没网络」最典型的形态。断电后路由器里的无线电路自己就恢复了，所以手机电脑照样能看到并连上这个 WiFi、也能拿到内网 IP。没有恢复的是 WAN 那一侧——路由器一直没能和 Telstra 重新建立线路，红色指示灯说的就是这件事。

What happened

发生了什么

This one was a returning client — we had installed the router for them back in April. They messaged around midday and we went out that afternoon.

Location: Waterloo, Sydney. Provider: Telstra. Router: ASUS. Plan: 100Mbps. Connection: DSL over the phone line.
What they reported: the power cable got knocked out; after plugging it back in, devices could connect to the WiFi but had no internet, and the indicator light was red.
Handled on-site rather than remotely, because separating a router hardware fault from a provider-side fault needs test gear you can swap in.

这位是老朋友返场——四月份帮他上门装的路由器。当天中午找过来，下午就随机上门去处理了。

基本信息：悉尼 Waterloo，运营商 Telstra，路由器 ASUS，宽带套餐 100 兆，联网方式是走电话线的 DSL。
原始反馈：不小心把电源线弄掉了，重新插上后能连上 WiFi 但是没有网络，指示灯是红色的。
处理方式是线下上门，而不是远程：要把路由器硬件故障和运营商侧故障分开，需要能换上去做对比的设备。

Why a router sometimes does not come back after a power cut

为什么断电之后路由器有时候回不来

For the large majority of routers, once power is restored the unit re-establishes the connection on its own — that is the normal behaviour and it is why most people never think about it. When it does not come back, the realistic causes are:

Router hardware. Unstable current or voltage during the interruption can leave an internal component misbehaving. Worth noting: some higher-end routers, ASUS units among them, draw more power than an ordinary router, which gives unstable supply a slightly better chance of causing trouble.
The provider side. The session the router had with the provider may need to be refreshed before it will come back.
Other equipment in the flat — an NBN box or an Opticomm device sitting in front of the router can also be the one that did not recover.

Which of the three it is cannot be guessed from the light alone. You bring known-good gear and rule them out one at a time.

对绝大部分路由器来说，电源重新可用之后，它会自行恢复联网——这才是正常表现，也是大多数人平时根本不会想到这件事的原因。如果重新通电后仍未恢复，比较现实的原因有：

路由器硬件故障。断电瞬间的电流电压不稳，有可能导致内部元件异常。另外要说一句：ASUS 等部分高端路由器功率高于普通路由器，受电源不稳定影响而出问题的概率会略高一些。
运营商原因。路由器和运营商之间的会话，有时需要那边刷新一下才能重新建立。
房间里的其他设备——挡在路由器前面的 nbn 盒子或者 opticomm 设备，也可能是没恢复的那一个。

具体是哪一种，光看指示灯是猜不出来的。得带上确定没问题的设备，挨个排查、逐个排除。

WiFi but no internet vs no WiFi at all有WiFi但没网络 vs 完全没有WiFi

	WiFi visible, no internet能连上WiFi但没网络	No WiFi at all根本搜不到WiFi
What it means说明什么	The router is alive; the link to the provider is not路由器活着，但和运营商的线路没通	The router itself is down or its wireless radio has failed路由器本身没工作，或无线部分坏了
Usually points at通常指向	WAN side: the line, the provider session, or an upstream boxWAN 侧：线路、运营商会话，或上游的盒子	Power, hardware failure, or wireless turned off供电、硬件故障，或无线被关掉了
First thing to check先看什么	The WAN or internet indicator, and whether a wired device also has no internet看 WAN / internet 指示灯，并试试有线设备是不是也没网	Whether the power indicator is on at all先看电源指示灯是不是亮的
This case本案例	Red indicator, WiFi joinable, no internet红灯，能连WiFi，没有网络	Not applicable不适用

How we isolated it, step by step怎么一步步定位

Confirmed the symptom on-site现场确认现象

WiFi joins fine, red indicator, no internet能连WiFi，红灯，无网络

Checked power and the DSL phone line seating检查供电与DSL电话线接口

Power restored, line physically seated供电已恢复，线接触正常

Ruled out other equipment in front of the router排除路由器前面的其他设备

No upstream box holding it down上游没有设备把它卡住

Reset the ASUS router对 ASUS 路由器进行重置

Router side cleared路由器这侧清干净

Had Telstra run a remote refresh on the service让 Telstra 后台做远程刷新

Line re-established, back online线路重新建立，恢复联网

What to try before calling anyone

在找人之前可以先试的

If your light goes red after a power interruption, a few minutes of your own can save a visit:

Give it time. A DSL line can take several minutes to re-synchronise after power is restored — do not judge it in the first thirty seconds.
Power everything down in order, wait a full minute, then bring the upstream box up first and the router second.
Plug a laptop into the router with a cable. If the wired device also has no internet, this is not a WiFi problem and you can stop fiddling with the wireless settings.
If the indicator is still red after that, call the provider and ask them to check the service and refresh it from their side — that is exactly what fixed this one.

如果断电之后灯变红了，自己花几分钟往往能省一趟上门：

先给它时间。DSL 线路在通电后重新同步可能要好几分钟——别在头三十秒就下结论。
按顺序断电：全部关掉，等满一分钟，先给上游的盒子通电，再给路由器通电。
拿网线把笔记本直连路由器。如果有线设备也没网，那就不是 WiFi 的问题，别再折腾无线设置了。
如果这些做完灯还是红的，就打运营商客服，让他们查一下服务状态并从后台刷新一次——这个案例最后就是这么解决的。

Result最终结果

Root cause was on the WAN side, not the WiFi: after the power interruption the ASUS router never re-established the line with Telstra, which is what the red indicator meant. Resetting the router plus a remote refresh run by Telstra on their side brought the 100Mbps DSL connection back. Worth remembering that higher-powered routers are a little more exposed to unstable supply than ordinary ones.

根因在 WAN 侧，不是 WiFi：断电之后这台 ASUS 路由器始终没能和 Telstra 重新建立线路，红灯说的就是这件事。对路由器做重置、再由 Telstra 从后台做一次远程刷新，100 兆的 DSL 就恢复了。顺带记住一点：功率更高的路由器，比普通路由器更容易受电源不稳的影响。

Waterloo: After the Power Cable Was Knocked Out, a Telstra DSL Line Came Back with a Red Light, WiFi but No Internet

Waterloo：电源线被碰掉后，Telstra DSL 恢复成红灯——有 WiFi 却没有网络

What happened

发生了什么

Why a router sometimes does not come back after a power cut

为什么断电之后路由器有时候回不来

What to try before calling anyone

在找人之前可以先试的

Related

相关链接

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遇到了类似的问题？