Spotty Comcast internet service. New Modem same thing

Zorachus

[H]F Junkie
Joined
Dec 17, 2006
Messages
10,087
I am on Comcast / xFinity Cable internet, been on it forever now, 10+ years, and it has been pretty stable and reliable for the most part of those ten years, I would say 85% stable. But more recently this year way less stable.

Well lately, since Spring almost, we get disconnected quite often especially on Saturday and Sunday mornings and afternoon. It will go offline, and say ' The DNS server isn't responding ' So I will unplug the Xfinity modem, wait 10 seconds, plug back in, and troubleshoot with Windows 10, and withing 5 minutes or so back on again, but then half hour later or hour will happen again, and same thing, and that can happen all morning and afternoon some days, but not all weekends. Seems weeknights when I game, it's 95% rock solid. But just the past week I started getting this issue, and I never had those issues ion late night game sessions before.

We have two gaming computers hooked up, and both the same issue, not just one PC.

So I went out and bought a $150 modem, hooked that up this weekend, called Comcast gave them the mac address to officially register it, all good for one day, rock solid, then Sunday morning, same disconnect again, same BS.

Help me [H]ard geeks, your my only hope. :)
 

Ocellaris

Fully [H]
Joined
Jan 1, 2008
Messages
19,072
Go to 192.168.100.1 and go find the logs and signal strength levels for the modem. That way you can diagnose the issue.
 

NoTrigger

Limp Gawd
Joined
Feb 18, 2011
Messages
148
Check for packet loss. Open up command prompt and type in "ping google.com -t" (without the quotes). This will continuously ping google's website until you stop it with CTRL+C, at which point it will give you a summary of the sent, received and a packet loss percentage

You should have a 0% packet loss, anything greater than that is unacceptable and involves more troubleshooting. Start by checking your coax lines and splitters. Unscrew the coaxial lines and check that the copper is not wet or rusted.

I had a similar issue as you described; however, mine involved a packet loss of 15% +. The Comcast technician that did the initial drop to my house (Coaxial line from the post to the splitter on the side of my home) ended up resting the coaxial line on the roof of my detached garage. Over time, the roof shingles ended up rubbing through the insulation all the way to the core and caused water to be soaking into the lines. They replaced the line twice and it came back each time until I finally got them to relocated the line.

Things of note if you don't have much experience with Comcast:
  • If you have coaxial lines on the inside of your home that need to be replaced, then Comcast consider it a chargeable fee. They only do the drops free of charge since that is what they consider on "their end." Coaxial lines are easy to run and not too expensive. The cost of the Coaxial spool I linked + tools and Connectors is less than the cost of them replacing a line.
  • If you're having a technician come out to your home to do troubleshooting, make sure they test the signals on your coaxial line with their handheld devices that connects directly to the coaxial (i.e. not a damn cellphone...). I had a technician come out that said my lines were find based on his company iPhone that pulled the status of my devices from my Comcast account. Had to have another technician come out because he is a tool.
  • Lastly, keep calling them if you're having issues. If you keep getting asked to restart your modem by the person on the phone, just tell them to transfer you to Level 2 support (they're the more technically competent people you can deal with).
They also do keep track of your call history, which you can use as reference for however long it takes for you to get it resolved. Use it to get a discount on your service.
 

trick0502

Supreme [H]ardness
Joined
Apr 17, 2006
Messages
5,499
A few things to look at. Comcast has an app to see the status of your connection. Use that to see if they show your modem as up or down. If it says it’s down it’s on Comcast and you’ll need their help to fix it. I think if you call and ask them they’ll have log of your modem going offline.

If it show online and your internet isn’t working a ping some stuff. Can your default gateway, 8.8.8.8 and www.google.com. Maybe factory reset your router and config it again.
 

Ocellaris

Fully [H]
Joined
Jan 1, 2008
Messages
19,072
Guys seriously, nearly every modem has a diagnostic/signal page at 192.168.100.1 and that should be the first place to check for errors.
 

cyclone3d

[H]F Junkie
Joined
Aug 16, 2004
Messages
14,864
As a previous Comcast customer... years ago, I am not surprised one bit. It does depend on where you are at though. In AZ, Comcast had great service and great customer service... this was 15+ years ago.

In AL, not so much.

When I first had it installed, it would not stay connected for very long at all. It took them 7 times of coming out to discover that there was a "test filter" on the line in the box that was supposedly causing the problem. They said it had been installed months prior, but in reality the box was a brand new install that had only been there a couple weeks.

Even after they removed that filter, I still had issues with the connection, but it was better than before.

Then, a family member got Comcast in their brand new house in a Comcast only neighborhood. They had massive issues with the modem even connecting. It got better after I fixed the Comcast installed wiring and bad grounding after they couldn't figure it out. The Comcast modem eventually got replaced by one I purchased because when it disconnected it would take anywhere from 5-45 minutes to reconnect.

Basically when it works, it works well. When you have problems, Comcast doesn't know their rear from their face and you are pretty much screwed unless you can fix it yourself.
 

Biznatch

2[H]4U
Joined
Nov 16, 2009
Messages
2,224
Eh, I wouldn't rely too heavily on the results of packet loss from a ping. ICMP is a really low priority packet, and a lot of servers will drop those without hesitation to prioritize other packets.
 

Mackintire

2[H]4U
Joined
Jun 28, 2004
Messages
2,936
First this:

"Go to 192.168.100.1 and go find the logs and signal strength levels for the modem. That way you can diagnose the issue."

You need a certain signal level in order for the modem to work properly. Its a 180' run from the Comcast mainline to my modem. That's why I ran the entire length as single piece of RG-11.


Second:

Zoom has some sort of secret sauce that allows their Cable modems to detect a connectivity problem and initiate a reset in a way that Motorola and Actiontech modems have been unable to. The result is the user's who have the Zoom Cable modems recover their connectivity more often without user interaction. If you've exhaused all the other explainations buy one:

https://www.amazon.com/5370-Certifi...d=1505327059&sr=1-3&keywords=zoom+cable+modem
 
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