Router showing modem at 100 Mbps suddenly

[sneak]

Everything was fine and I had a loud sound outside due to lightning, my UPS shut off along with everything connected to it (including modem and router). My 2.5 GbE PCIE wasn't showing up in Windows after turning everything on. I pulled it out and observed visible damage on the back of the PCB. My router port 4 also doesn't work anymore. I can't seem to get my router to stop showing my modem's port speed as 100 Mbps, and it's heavily crimping my speeds.


Here is the gear:

• Hitron CODA56
• ASUS RT-BE86U (Merlin 3006.102.3)
• Cat6 cables
• TERRAMASTER F4 424-Pro
• ASRock X570 Taichi

Originally I was using LAN 1 for my work PC but right now I don't have a work PC and should receive a new one tomorrow, so I have an ethernet cable hanging out of LAN 1 not connected to anything. LAN 2 has a cable connected to my NAS (prior to LAN 4 on the router breaking I was using LACP with ports 1 and 2 on the NAS but I've disabled all that and I'm just using 1 cable now). LAN 3 has my computer connected to it.

Router page shows LAN port 1 as inactive as well as port 4, since port 4 has nothing connected and port 1 has a cable only connected on the router side. Nothing wrong with that.

Router shows LAN port 2 as "2.5 Gbps" when hovering, which is correct as it's connected to the NAS. LAN port 3 shows "1 Gbps", which is correct as it's connected to my PC motherboard, which doesn't support 2.5. The issue comes with the router reporting the "10G WAN/LAN 1" as "100 Mbps". It has marked it yellow. This was the issue I had in the past, but it was with the LAN ports and a different cable resolved it. I have tried 4 cables and cannot get this thing to read properly. I've tried power cycling the modem, and the router. There is also some information (see attached file) provided by the router.

I called my ISP to see if they're doing something weird after getting people's connections restored today and they told me they see something weird with the signal since yesterday. I wasn't having issues yesterday. They're sending someone out tomorrow..

 

[Tech9]

If everything connected to this port (modem or router side) shows 100Mbps only - it got damaged. What usually damages is the transformers behind the port. Depending on what pair was damaged - you get 100Mbps or nothing.

 

[sneak]

It is the WAN port so the only thing connected is the modem. I don't have any other modems to connect to it.

I guess my only options are to connect the modem directly to my PC and see if it still shows 100 Mbps. If it does the modem is faulty, if it doesn't the router is faulty?

 

[Tech9]

Don’t change the default font colour. Your colour choice makes the text hard to read on Default and Light forum styles.

This connection has two ends. If your cable is good - it’s most likely one of the two LAN ports involved. In some cases both ports may have suffered damage.

 

[sneak]

Don’t change the default font colour. Your colour choice makes the text hard to read on Default and Light forum styles.

I didn't change anything. Not sure what you're seeing, but it looks normal to me.

EDIT: I switched site to light mode and see it. I didn't change it but I figure it's something to do with the forum software used. When I was trying to post the reply the internet randomly went out and I noticed the modem was rebooting. Not sure what happened with that, but I had copied what I already tried to reply with and pasted it once the internet went back up. The forum probably did that on it's own. I edited the text back to normal.

 

[tgl]

Back to the point ... I agree with @Tech9 that either the router's WAN port or the modem's local port is partially fried. Maybe both . Your ISP's service person will be able to test the modem, and hopefully will replace it if bad, so just wait for that visit. If your luck is bad you will be looking at having to replace the router. I am a little bit optimistic that it might be the modem, since the ISP say they can see something is wrong; but that's not certain.

 

[sneak]

Back to the point ... I agree with @Tech9 that either the router's WAN port or the modem's local port is partially fried. Maybe both . Your ISP's service person will be able to test the modem, and hopefully will replace it if bad, so just wait for that visit. If your luck is bad you will be looking at having to replace the router. I am a little bit optimistic that it might be the modem, since the ISP say they can see something is wrong; but that's not certain.

Thanks. They're not going to replace it as it's my own. But that's a good point that they should be able to test it and make sure it can switch to the right mode.

 

[degrub]

You can swap out the cable between the two with a known good cable just to rule that out. Otherwise, likely as above.
And if one port or both were damaged, expect to replace other equipment in the house in the future. If you are really lucky, the surge came in on the external cable to the modem. If you are unlucky and the surge came in on the earthing connection/neutral connection, other devices are likely to be affected. It may not show up for a few months though.

 

[fryedchikin]

Thanks. They're not going to replace it as it's my own. But that's a good point that they should be able to test it and make sure it can switch to the right mode.

It's a long shot, but you might ask for an ISP tech to physically inspect the routing of the coax to your building to ensure it was grounded appropriately when installed. Sadly, it is quite common for these to be run by contractors who don't know or care about doing it correctly. If something was missed, they may be liable for replacing any damaged equipment.

 

[sneak]

You can swap out the cable between the two with a known good cable just to rule that out. Otherwise, likely as above.
And if one port or both were damaged, expect to replace other equipment in the house in the future. If you are really lucky, the surge came in on the external cable to the modem. If you are unlucky and the surge came in on the earthing connection/neutral connection, other devices are likely to be affected. It may not show up for a few months though.

Already tried 4 cables.

It's a long shot, but you might ask for an ISP tech to physically inspect the routing of the coax to your building to ensure it was grounded appropriately when installed. Sadly, it is quite common for these to be run by contractors who don't know or care about doing it correctly. If something was missed, they may be liable for replacing any damaged equipment.

If you're talking about the box on the back of the house they checked that in April when fixing signal issues. Brand new connector and checked signal and everything, and removed useless splitters in my attic.

 

[RMerlin]

If you have a laptop with an Ethernet jack, do a quick test by plugging the laptop directly to the modem, then directly to the router's WAN port, and check the link rate reported by the laptop in both situations. It might help you pinpoint if there is an issue with the Ethernet port of either of these two devices.

 

[sneak]

If you have a laptop with an Ethernet jack, do a quick test by plugging the laptop directly to the modem, then directly to the router's WAN port, and check the link rate reported by the laptop in both situations. It might help you pinpoint if there is an issue with the Ethernet port of either of these two devices.

That's a great idea I hadn't thought of because I haven't used my laptop since July due not using my computer for work since then. However at this point I'm probably going to wait for the ISP since they're going to come anyway, and I could use the laptop as 3rd confirmation before buying anything -- especially so that I can see if the router is broke IN ADDITION to the modem.


unrelated funny rant if interested:
The person from the ISP came already, supposedly. They told me (as usual, but doesn't make much sense) that their window for the visit is basically their entire window of 8-5. They asked for a preference and I said 1 PM. I got up at 10, because they NEVER come very early. They called at 9:12 AM and I missed the call. They left a voicemail at 9:13 AM stating they're "on the way over". I called twice at 10 and got no answer, so I called the ISP back and they told me the person put in the notes they arrived at 9:10, knocked, no answer, and left at 9:25. Interesting how they can arrive 2 minutes prior to the time they were on the way. I asked about doorbell and she told me "well they do a police knock" and asked if I'd like them to ring the bell this time. I said yes, and told her I thought it was standard that if a bell exists someone rings it. She said "well they don't know if the doorbell works so they knock". I told her if they'd ring the bell they would know if it works because they could hear it... Also, why operate on the idea the bell doesn't work?

EDIT:
ISP came and got 94 Mbps as well through their tool, directly connected to the modem. They checked the coax at the wall in the room and got over 2 gigs. Will get a new modem.... again.

 

[Tech9]

Modem only is not a big loss. Surprised you have your own CODA56. ISPs around here were sending them out for free when DOCSIS 3.1 become the minimum supported standard. I have two from my ISPs, no idea how much they cost.

 

[sneak]

Modem only is not a big loss. Surprised you have your own CODA56. ISPs around here were sending them out for free when DOCSIS 3.1 become the minimum supported standard. I have two from my ISPs, no idea how much they cost.

Modem, TRENDnet TEG-25GECTX, LAN port 4 on ASUS RT-BE86U. For now that's all I'm aware of losing.

My ISP has the option to rent combo router/modems but I prefer to have a non-combo and my own, separate units. They're rolling out fiber and providing free ONTs for that instead.

I purchased a used (claimed about 9 months) CODA56 for $98.90 ($10.94 of it is shipping, and $7.96 is tax). They go for about $150 + tax/shipping new, normally.