Re: Frustration (cablemodem woes)
Michael Patterson, 2001-Nov-12 11:14 -0700:
> > Does it take a long time to initially make the connection to a
> > web site and then after it finally connects the web page popps up
> > quickly?
>
> The web page takes a noticable, but not prohibitively long time to connect.
> it appears that the site "www.thex-files" (to name a specific page) will
> load part of the flash presentation, then pause for a long period of time
> before continuing.
This mostly rules out a dns issue, if you connect to the desired
web site quickly and start downloading.
> > Do downloads go really slow? Do uploads go really slow?
>
> Downloads go extremely slow. The "game of the hour" here is Dark Age of
> Camelot, and I've been using the install of this program as a method of
> testing download speeds. (it gives a download rate while updating over the
> net)
>
> A win98 machine hooked directly to the cablemodem gets 60k/sec download.
> A win98 machine masqueraded through my debian box on wantweb gets 10k/sec.
> A win98 masqueraded through my debian box on the cablemodem gets 0.3k/sec
> before stopping entirely.
>
> The fact that DaoC stops downloading entirely after a short period of time
> is puzzling. It worked fine with masquerading through wantweb.
>
> As a second test to verify, I told Morpheus to download a number of files at
> once. It seems to be doing significantly better. The speed of the files
> being downloaded adds up to 12k/sec.
I believe there is a layer 1 or 2 problem here.
> > Does network traffic simply stop altogether for a period of time?
>
> Yes. Eventually, the traffic stops completely, requiring a reboot of the
> cable modem for it to start up again.
I can think of 2 things that may be at issue: 1) your cable
modem could be losing it's registration on the cable loop, which
means the cable head-end no longer see's it on the loop and stops
forwarding traffic onto the loop for it until it recieves
registration packets from it again. This would be a cable
provider problem, but you cable guy say's the modem is
fine...hmmm. 2) you NIC is bad and either the NIC just goes
belly-up after awhile or it's sending garbled packets which the
modem eventually just stops listening to. You'll need a new NIC
(known to be good) to swap out and test.
> > Add anything else you can think of.
>
> I had someone come out from the cable company to check my setup. They
> verified that the cablemodem was working fine (which I also verified by
> hookng up a win98 box directly to it).
>
> The connection has stoped three times since I started this email. In all
> cases, the "PC" light has remained on, and the cable light has blinked
> slowly (in normal behavior, the PC light blinks off with traffic, and the
> cable light blinks faster as traffic is transmitted). The modem is a
> scientific atlantic.
This particular cable modem's status light blinks to indicate one of
the following conditions:
- The cable modem is booting up and not ready for data.
- The cable modem is scanning the network and attempting to register.
- The cable modem has lost registration on the network, and will continue
blinking until it registers again.
> > Also, check your /var/log/syslog file for messages regarding
> > dhcp, your ethernet interface and aything else suspicious.
>
> There is one string of messages that appears suspicious, and repeats itself
> over and over again.
>
> Nov 12 10:51:47 white kernel: Packet log: input DENY eth0 PROTO=17
> 24.8.30.89:13
> 7 24.8.30.255:137 L=96 S=0x00 I=148 F=0x0000 T=64 (#7)
Looks like you firewall is denying and logging packets it's
recieving for the qotd protocol...qotd 17/tcp "Quote of the Day".
I don't know of an exploit that this might indicate, but it
doesn't have an effect on the problem at hand.
jc
--
Jeff Coppock Systems Engineer
Diggin' Debian Admin and User
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