Member Avatar for Oeggy

I have three computers connected via wired method to a 4-port Linksys router. Everything has been working fine for the last several months. Today, connectivity has been very erratic. Cable company says everything is fine on their end. I've done nothing differently, software or hardware wise to cause any changes.

If I unplug the router and then plug it back in, I will have restored connectivity for about 10 minutes. Then it's dead in the water. So I thought maybe the router is going bad?

But if I plug the cable modem directly into my computer, I get *NOTHING*. It thinks I'm working offline. I can't connect at all! So I thought maybe the modem is going bad?

But do modems "go" bad? Doesn't it either work or not work? Why would it work for a few minutes before dying?

I don't know much about the intricacies of networking. Everything plugs in, I don't do anything fancy, just want to get on the internet. All worked fine until today. Any tips would be helpful.

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Brief, practical diagnostic steps to determine whether the cable modem, the Linksys router, or something in-between is at fault for the intermittent drops described by . This builds on the pointers from , and by giving an ordered, evidence-first workflow and specific checks to record before changing firmware or replacing gear. (support.usr.com)

Isolate to one machine and gather facts: disconnect the router and attach a single PC directly to the modem with a known-good Ethernet cable. Record the adapter state and DHCP lease using standard Windows commands so the lease type and any 169.254.x.x (APIPA) addresses are visible:

ipconfig /all
ipconfig /release
ipconfig /renew

If the PC never gets a public IP or shows 169.x.x.x, that points at the modem/ISP DHCP step rather than the LAN. Capture the output and note the default gateway and DNS entries for later. (learn.microsoft.com)

If the direct-PC test fails, check the modem’s built-in status page (many DOCSIS modems expose it on 192.168.100.1) and look at downstream/upstream channel status, SNR and power levels. Large deviations, missing channels, or “not registered” status indicate a DOCSIS/RF problem that the ISP must fix. Typical vendor guidance lists acceptable downstream power roughly within -15 to +15 dBmV and warns that SNR and upstream power outside the vendor ranges cause instability — capture screenshots or photos for tech support. (arris.my.salesforce-sites.com)

If the modem looks healthy, concentrate on the router: test with a different router (or factory-reset the Linksys, after saving its config), use a minimal config (WAN=DHCP, no port forwarding/QoS), swap Ethernet ports/cables, and monitor router logs and temperatures. When rebooting the chain, follow the modem→router→clients sequence and wait for the modem to show “online” before powering the router. If problems persist and modem status shows marginal numbers or frequent reboots, provide those status pages and timestamps to the ISP for escalation. (support.linksys.com)

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Member Avatar for bentkey

When you plug your pc directly into the cable modem, you may have to configure the IP settings if they are not automatic from your ISP. But you will definetly have to power the cable modem off and back on after you connect your home PC. They tend to remember the MAC address of the last device they were connected to and won't just accept a new one because you plug it in. You can also check that the router is not getting hot. Sometimes if you stack these things they will get hot in a short period of time and start acting up.

Member Avatar for Oeggy

Thank you for the modem information, Bentkey, I hadn't recycled it after plugging it in. I will try that later. This morning (like yesterday morning) I've been on now for much longer than the 10-minute cutoffs I was experiencing all day yesterday, which makes me wonder about my ISP. But I will try plugging the modem in directly later on and running the Linksys router wizard again.

Hate to piggyback questions, but at the Linksys site they recommend upgrading firmware. I downloaded the newest firmware but haven't installed it yet. I've never upgraded firmware. Is this like installing new video drivers? Is this something I ought to be doing more often?

Member Avatar for alc6379

I wouldn't upgrade the firmware drivers unless you actually have a reason to do it. If you botch it, you could render your router useless. If it ain't broke, don't fix it!

In a case like this, I would recommend upgrading the firmware, too. The Linksys site should provide instructions for installing the upgrade.

Note: you weren't "piggybacking" this question-- it was related to your original issue! :D

Member Avatar for DMR

Is this like installing new video drivers?

Much more like like flash-upgrading your computer's BIOS, and as alc6379 mentioned, you shouldn't do it unless you're positive that it will fix your specific problem- a botched firmware upgrade can definitely turn your router into a paperweight.

A lot of manufacturers will suggest upgrading firmware, drivers, and the like as part of their "canned answer" to a wide variety of problems, but since you say that the router worked fine for months and that you've made no changes, I'd hold off on the firmware upgrade until you've eliminated any other possibilities.

Try bentkey's suggestion first; the modem does need to be turned off if you connect a different device to it, and yes- you may need to adjust the network settings on the computer.

Both routers and modems can fail in "soft" ways; a defective device could definitely exhibit the symptoms you describe.

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