Re: Help needed with intermittent internet
- From: "JM" <jake@xxxxxxxxx>
- Date: Mon, 30 Apr 2007 15:28:29 -0500
A customer of mine (I'm an IT-for-hire person) has Comcast business class
cable internet service. A few weeks ago they started experiencing
intermittent internet. They have a Comcast/Netgear combo device
(router/modem/firewall) that we have configured for what they call "router
mode," which I call "bridge mode." Either way, we have a static IP
address that is passed through to our LAN, NAT and firewall in the device
turned off. I have the IP address configured on one of the NICs in a
Novell server. The second NIC in the server is for the LAN, with the
server giving out DHCP. There have been no problems there. The Novell
server also is our main app server and our email (Groupwise) server. When
the internet is down, everything else works fine. And I changed out the
WAN NIC twice. Point being there are no indications that the server is
behaving in a way that would cause the internet problems.
Each morning when they show up for work the internet is down. They call
me, and I start trying to ping both the IP of the Netgear (gateway
address) and the server (static IP). Usually, I cannot get a response
from either address. Occasionally I can get a response from the gateway,
but not the server (and of course I can never get the server and not the
gateway). This weekend I performed random ping tests to the gateway, and
I caught it down at least 5 times.
Comcast has changed out the Netgear unit 2 times (meaning we've had 3 of
the units). They monitored the device for several days and say it does
not go "off-line." However, this morning they told me that, yet neither
I nor the support rep could ping the gateway. She offered to "reset the
modem" for me. As soon as she did, I could ping the gateway, the server,
and the internet was up at the office.
Comcast's theory - after many, many support calls, as well as changing
out the box twice - is that something on the client's network side is
"locking up" their device (the Netgear).
Does that make any sense?
Thank you very much for your excellent reply.
Here are some answers (I'll get other answers this evening).
You start by saying that there are intermittent outages, but you only
specifically mention it being down first thing in the morning. Are there
on-going problems at random times during the day, or is this only
happening when the connection has been idle for some time?
It happens throughout the day, mostly on the server's static address (for
terminology clarification, I'll use "gateway" address and "server" address
from now on). This fact led Comcast to conclude pretty early on that the
problem was on our side, since when we called during the day they could ping
the gateway address. That was reasonable, enough, until I started finding
the gateway address down at certain times, too, and often it's down in the
morning. However, over the weekend, I had failed ping tests to the gateway
at various times, day and night. Another fact perhaps worth mentioning is
that every workstation in the business is turned off at night and weekends.
So whatever is happening along the lines of Comcast's theory is limited
solely to server activity. In other words, if some activity on the lan side
indeed is "locking up" the Netgear, it's emanating from the server, not a
workstation, i.e., a malware-infected computer flooding the network. (and
I'm being open-minded, but I have my doubts in any event that something
lan-side could indeed lock up a cable modem). In general, there seems to be
no relationship to idle time.
If the problem appears often after the use of the Internet connection has
been unused for a period of time, then I would check to see if the server
is shutting down the NIC because of some power management setting.
This does not appear to be the case.
Also, if it only happens overnight, set it up to run ping continuously
overnight, and see if the problem goes away.
As mentioned, it happens day and night.
Something else you could try is instead of having the Novell server
connected to the Internet, connect a different system. Of course this
wouldn't be practical during the work day, so you'd probably have to do
this over the weekend. Make sure there are no power management settings to
shut parts of that system down when idle, and test to see if the Internet
connection goes down.
That is my plan for tonight. I'm going down there in a little while to
connect a newly-formatted PC to the connection. That should be very
informative.
BTW... You don't mention how you get the connection back up when it goes
down. Are you rebooting the server? Power-cycling the modem? Calling
Comcast, and having them reset the modem remotely? What does, and what
doesn't work to bring the connection back up?
That is another strange aspect to the story. For 3 straight days, the modem
began working again during my call to Comcast. I would call in, and after
identifying the customer the Comcast rep would attempt to log in to the
Netgear to "take a look." The router would start working immediately. In
fact, during that 3-4 day stretch, one of the reps and I used the "sleep
mode" analogy, such as you mentioned with the power management suggestions.
However, many Comcast folks have assured me the Netgear has no sleep mode.
This morning when I called in, the Comcast rep offered to reset the modem,
which brought the internet back up. When I said that indicated a problem on
their end (or with their equipment), she reiterated Comcast's position that
since they've swapped the unit out twice the problem MUST be on the client
side. They think something is locking the Netgear up, requiring a reset
sometimes, while other times not.
jm
.
- References:
- Help needed with intermittent internet
- From: JM
- Re: Help needed with intermittent internet
- From: Warren H
- Help needed with intermittent internet
- Prev by Date: Re: Custom Cable tv
- Previous by thread: Re: Help needed with intermittent internet
- Index(es):
Relevant Pages
|
