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zigzag · 04:34 PM

Starting a couple of weeks ago, my internet connection (cable) started cutting out for no apparent reason. The signal is good (I checked with Comcast, and all lights on the modem are strong, including the activity light). Comcast told me to restart both the Mac and the modem, which solves the problem but is very annoying to do 3-4 times a day, and I'm tired of getting cut off in the middle of a download.

When it started, I noticed that if I waited perhaps an hour, the connection would restore itself. This made me think that it was just a Comcast outage, but apparently that's not the case.

Any thoughts on what the problem might be without having to bring a Comcast tech out to screw with my Mac? I'm a complete neophyte when it comes to networking so please make any explanations in very plain English.

[Update: I've discovered that unpluggung/restarting the modem alone seems to solve the problem, at least until the next cut-out. Any thoughts?]

Thanks very much for any input.

iMac 800 FP, Motorola Surfboard cable modem, using DHCP on "automatic/built-in ethernet"

l008com · Aug 20, 2003, 07:43 PM

I used to and sometimes still have the same problem. It used to happen all the time, and an upgrade to a modern modem from an 8 year old one solved that. Now it only rarely happens, and the culprit is KaZaA. The real PC client on a PC, or one of the many Mac Clients. Either one will kill your modem and require you to restart it. My guess is that it tried to connect to so many different other clients at once, that it maxes out your modem and it stops transmitting.

kampl · Aug 20, 2003, 09:22 PM

W32.Blaster has been bangin away for a couple weeks now, and W32.Welchia is on the scene now too making life in the networking business miserable. I can personally vouch for Verizon ADSL service being crap since these both reared their ugly heads. I've been getting quad digit ping times to my default router!!!! I've never seen a default router take three and a half seconds to respond to an echo before. Freaky.

l008com · Aug 20, 2003, 09:38 PM

what is that the latest windows virus?

kampl · Aug 20, 2003, 09:48 PM

W32.Welchia is the most recent Windows worm that is exploiting the same RPC flaw that W32.Blaster is exploiting. This one's propogation methods create an ICMP echo flood as it is trying to find other hosts to infect. In my experience anyway.

zigzag · Aug 20, 2003, 11:27 PM

Originally posted by l008com:
I used to and sometimes still have the same problem. It used to happen all the time, and an upgrade to a modern modem from an 8 year old one solved that. Now it only rarely happens, and the culprit is KaZaA. The real PC client on a PC, or one of the many Mac Clients. Either one will kill your modem and require you to restart it. My guess is that it tried to connect to so many different other clients at once, that it maxes out your modem and it stops transmitting.

I haven't used any Kazaa clients as far as I know. But I'll check with Comcast about a new modem, although I fully expect them to say it's the iMac's fault.

Thanks.

zigzag · Aug 20, 2003, 11:36 PM

Originally posted by kampl:
W32.Blaster has been bangin away for a couple weeks now, and W32.Welchia is on the scene now too making life in the networking business miserable. I can personally vouch for Verizon ADSL service being crap since these both reared their ugly heads. I've been getting quad digit ping times to my default router!!!! I've never seen a default router take three and a half seconds to respond to an echo before. Freaky.

OK, I appreciate the tip but I have no idea what you're talking about. Do you think this might have some effect on my Mac's connection? Is there anything I can do about it? Thanks.

superlarry · Aug 21, 2003, 06:19 AM

there's just a lot of network traffic being generated by these two worms, which could be causing problems at comcast. i think this is a possibility if your problems haven't started until recently (i think within the last week).
as a mac user, there's nothing you can do about it. win2k/xp users should install the patch from microsoft to stop their computers from being affected and propagating the problem.

zigzag · Aug 21, 2003, 09:55 AM

Thanks, superlarry, I'll ask Comcast if that might be the problem.

zigzag · Aug 28, 2003, 07:35 PM

For anyone who's interested, I haven't had any cut-outs since the day after I last posted. I never talked to Comcast about it, but this suggests to me that a worm could have been screwing up their network, as kampl and superlarry suggested. Thanks for the help.

ghporter · Aug 29, 2003, 09:18 AM

Don't forget Sobig. It is another bandwidth hog of a worm/trojan that affects Windows platforms. This means a lot to the Mac community, because there are so many Windows machines out there (and so many stupid users that don't do anything to protect themselves from infection) that the entire Internet gets slowed down-often drastically-by all the crap traffic that these viruses generate. ISPs are often bottlenecks when one of these stupid things starts up, and that means your connection can slow to a crawl, or worse.

And we shouldn't be too smug in using Macs and thinking they're immune to viri. They aren't. It's just that the script kiddies and bad guys have such a rich target audience in Windows platforms that they haven't bothered too much with Mac OS bugs. On the other hand, MS Office has quite a bit of commonality between Windows and Mac versions, so anything that exploits a weakness in Office is a danger to us as well.