# [SOLVED] Comcast Connection Randomly Dropping



## nthexwn (Sep 25, 2007)

Hey guys,

I'm usually pretty good with computer hardware, but I _really_ dislike networking. I've been plagued by a problem for several years now that I've never gotten a straight answer too.

On several different computers at several different locations I've always had a problem with my connection stopping for no apparent reason. My computer works fine, none of the lights on the cable modem turn off, but the connection just stops entirely. This usually happens while I'm playing various games and suddenly stop receiving packets from the server. I usually alt+tab, open Firefox, and check to see if I can access Google. Most of the time I can't and the connection remains completely dead for the next couple of days. Strangely enough I can usually still renew my IP address (until the first time I reboot) and the basic Windows tools will claim that everything is working fine. I'm sure if I knew how to poke around with certain software tools I could figure out exactly what's stopped working, but I don't know how to do that on my own.

The only solution I've found to these random connection drops (aside from just hoping they won't happen) is to unplug power to the modem and leave it unplugged for _half an hour_ (Tech support tells me 30 seconds but I've found that this often isn't enough) and then boot the modem back up and let all the lights turn on before connecting it to the PC. If I plug it into the PC while the PC is on then it often won't work, so I usually have to power down the PC before plugging the networking cord back in. Since I have to wait so long (usually 30 minutes) before the modem will work again this leads me to believe it might be an overheating issue, but that's just a wild guess.

This has always been worse when my computer has been connected to a switch/router rather than directly connected to the modem. When I was living in a house with 6 other people we could never get the connection to stay online for more than a few days before it dropped for some or all of us. I'd have to randomly power cycle the router/modem, and plug/unplug people's connections and add them back one by one. Sometimes some of us would be unable to get a connection and other times things would actually work out. It was a compete nightmare! I tried using multiple switches/hubs, upgrading their firmware, and blocking certain ports from the control panels (file-sharing). I even went back to Comcast and got a new modem at one point just in case the current one was the culprit. Nothing I tried _ever_ made the problems go away for good.

Nowadays I'm living on my own and have my own connection hooked up to a single computer so I don't need a router. Unfortunately our apartment complex is wired very shoddily so the Comcast technician told me that the wire to my room couldn't hold a signal, so he'd have to divert the main line in my unit directly to my room. This was good because nobody else in my unit has an internet connection, so I had the line all to myself. However, somebody just moved in that's requesting a connection and since the line is going directly to my room now that means they can't split it off to his as well without tearing down some walls. As such, I'm probably going to have to split the connection/cost with the other guy now, and this means setting up a router again. I'm almost certain that this will turn into another nightmare like at the old house.

I don't know why this stuff is so hard for me. I'm not exactly an expert but I've got an A+ cert and have built several of my own computers as well as working in some small shops. Like I said, I know my hardware, I just cannot for the life of me troubleshoot this networking stuff.

I need help guys, and I don't know where to ask for it, which is why I'm here. I need to figure out why my connection is dropping (about once a week at present) and how to manage a router so that it doesn't cause the connection to die even _more_ frequently.

I'm willing to delve into tutorials, programs, and any other stuff provided just as long as I don't get any mis-information. I'm willing to swallow my pride, assume I know nothing, and repeat steps I've completed before. I'll tell you anything you need to know about my setup.

I want to solve the short-term problem of this connection dying, but I'm also hoping for knowledge so that I can figure out what's going on in the future. Sorry for ranting so much, but I've spent days and days worth of time dealing with this crap in the past and it's time for the headaches to finally end.

Thanks a ton,
Alex


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## BMR777 (Apr 27, 2005)

*Re: Comcast Connection Randomly Dropping*

While online, try typing http://192.168.100.1 into your browser. This may let you into the Comcast modem's control panel if you have one of the motorola models. There are some logs in there.

Is there a router between your PC and the modem or is it a straight-on connection PC to modem?

BMR777


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## nthexwn (Sep 25, 2007)

*Re: Comcast Connection Randomly Dropping*



BMR777 said:


> While online, try typing http://192.168.100.1 into your browser. This may let you into the Comcast modem's control panel if you have one of the motorola models. There are some logs in there.
> 
> Is there a router between your PC and the modem or is it a straight-on connection PC to modem?
> 
> BMR777


Ah, good to know about that. Thanks. For some reason I kept trying 192.168.0.1, but I suppose that's only for routers? I really don't know what I'm looking at here and don't recall what times match up with what I was doing. It also doesn't help that I've somehow gotten my modem to think it's 1970. What am I looking for here? What should I watch out for in the future?

http://img.photobucket.com/albums/v28/nthexwn/ModemLogs.jpg

I was using a direct connection to the modem, but as I feared the new guy required that I split the connection by using an old Netgear FS105 switch.

After hooking it up and running my cable to the switch instead of to the modem my computer was no longer able to acquire an IP address. I tried power-cycling both the modem and the router to see if that would help but it didn't work. I also tried to release/renew both via right-clicking and selecting repair and then by typing ipconfig /release, followed by ipconfig /renew in the command prompt. This didn't help either. The connection was working fine for the other guy so I tried swapping the physical ports that we were using. His connection came back up and mine was still having troubles acquiring an IP address. On both instances I tried a release/renew. I figured maybe there was something funky with the cable, so I tried swapping the cables that we were using. Again, his computer was getting a connection and mine wasn't. Not giving up quite yet, I tried switching the NIC on my PC (my motherboard has two network controllers) and repeating all of the above steps. Again, that didn't help. After that I spent some time on my own randomly power-cycling, plugging-unplugging, etc. in the hopes that something I did would fix the problem. While doing this I noticed that one of the NICs was only _receiving_ packets and one of them was only _sending_ packets. I figured maybe for some strange reason plugging them both in at the same time and bridging the network connections would work. Unique thinking I suppose, but it didn't do anything.

Well, now several hours later I'm finally online, but I'm not sure what exactly I did that made it work. I don't know what it is about my computer that makes it unable to connect through a router/switch, but like I said in my first post, I've _always_ had issues with it at different locations using different hardware (including different switches/routers). I'm almost certain that either the other guy won't be able to connect now for the same reasons, or that my connection will randomly drop within a few days as it has in the past in these situations. I'm very confused and would appreciate any advice!

Thanks,
Alex


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## BMR777 (Apr 27, 2005)

*Re: Comcast Connection Randomly Dropping*

If I remember correctly a switch will not assign out IP addresses for clients, whereas a router will. What this means, and I could be wrong here, is that there is a possibility that there is only one IP address available from Comcast, and since you are using a switch there is only one IP address available for two clients, thus someone can't connect. I could be wrong, though.

As far as the problems you are having go, it could very well be a signal issue. Also when I had major network problems with Comcast it was due to a faulty cable filter on the cable line. This is located in the box controlled by Comcast along the street and determines what cable channels a person gets with the old Analog cable. A faulty one of these caused me to have similar issues in the past with Comcast.

BMR777


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## nthexwn (Sep 25, 2007)

*Re: Comcast Connection Randomly Dropping*



BMR777 said:


> If I remember correctly a switch will not assign out IP addresses for clients, whereas a router will. What this means, and I could be wrong here, is that there is a possibility that there is only one IP address available from Comcast, and since you are using a switch there is only one IP address available for two clients, thus someone can't connect. I could be wrong, though.
> 
> As far as the problems you are having go, it could very well be a signal issue. Also when I had major network problems with Comcast it was due to a faulty cable filter on the cable line. This is located in the box controlled by Comcast along the street and determines what cable channels a person gets with the old Analog cable. A faulty one of these caused me to have similar issues in the past with Comcast.
> 
> BMR777


Well, as I feared, the guy in the other apartment couldn't get a signal after it started working for me. I took your advice and swapped the switch with a real router. Now everything is working! Thanks! The only real problem is that he's hooked up wirelessly now, which could cause bandwidth headaches if somebody decides to steal the signal. We set up WPA access for him, but I still don't trust it because I've heard of it being cracked before. We're also in the middle of a university area so the people who would be most likely to do that and also have the knowledge to do so probably wouldn't be too far away. I guess I'm just paranoid though. (I love my good old-fashioned wires!)

Maybe you're right about the signal quality. This building is really old and like I said in the first post, some of the existing cable lines aren't able to carry a signal. I guess I'll just hope it doesn't crash on me too often now that two people are connected through the line I've been using. In a weird sort of way that answer actually makes me feel better because it would mean I wasn't really doing anything wrong in the first place like I thought I must be.

Thanks again,
Alex


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## johnwill (Sep 26, 2002)

*Re: Comcast Connection Randomly Dropping*

WPA has never been cracked. The only known attack is a dictionary attack for weak passwords. If you use a long and random password, I can assure you your WPA link will be quite safe. Suggested password? "kieweksoyqUYVV1857xyBB"

Remember, case matters! :smile:


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## nthexwn (Sep 25, 2007)

*Re: Comcast Connection Randomly Dropping*



johnwill said:


> WPA has never been cracked. The only known attack is a dictionary attack for weak passwords. If you use a long and random password, I can assure you your WPA link will be quite safe. Suggested password? "kieweksoyqUYVV1857xyBB"
> 
> Remember, case matters! :smile:


Good to know. In that case everything should be fine.


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## kbd_usr (Jun 20, 2007)

*Re: Comcast Connection Randomly Dropping*

It's all over. THere's glitches galore. Don't believe it?:

Search for the word "BUY". It's quite interesting.


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## johnwill (Sep 26, 2002)

*Re: Comcast Connection Randomly Dropping*

*kbd_usr*, what on earth are you talking about? Do you have a purpose in posting to this thread?


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## kbd_usr (Jun 20, 2007)

*Re: Comcast Connection Randomly Dropping*

Yeah, glithch es. There known to happen.
I'm speaking in general terms, that maybe no user intervention is required. What for it to stabilize.

And, the Earth is the planet your on, right now. BTW.


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## johnwill (Sep 26, 2002)

*kbd_usr*, in the future, please confine comments to useful information that is on-topic. Since this problem was resolved, I have no idea why you felt compelled to post a nonsensical comment.


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