Is this true? The past few days my usual 2.5-3.0Mbs speed dropped to
1/10 of that. Then yesterday it basically ground to a halt. I called
comcast again and they claimed there were DNS problems affecting the
entire US. Anyone else have internet connectivity issues late yesterday
afternoon or evening?
I found nothing in the news about it.
There weren't any DNS problems that I noticed on my Comcast feed 40 miles
north of you, Dave. At least after 8:30 pm, when I got home, things were
Stuff happens. Tech support doesn't understand it until they fix it, and
then, still maybe not. It's a miserable job to have to do for any length
Internet Name Servers are built on a pyramid scheme!
Because I haven't seen any problem on my specific segment ( I haven't) does
not mean that your Comcast scheme of hierarchy of DNS servers couldn't be
having problems. Your setup thru Comcast may have a primary and secondary
DNS and these could be local to you and having problems, but that does not
mean EVERY where there is a problem.
Next time: try to use the command prompt (black screen) mini-app
nslookup.exe. You should be able to google nslookup, Microsoft Knowledge
Base nslookup, or many computer books for command line switches.
example: nslookup -q/A www.woodcraft.com
returns an address: 64. 181.11.11
if you get a timeout or other failure message, then you primary DNS may
indeed have a problem.
try a site on the East Coast (www.irs.gov)
a site down south (www.peachtree.com)
a site in Chicago (www.sears.com)
and the West Coast. (www.oscars.org)
and you can find out if just a segment of the geographical US could be
Yep, just outside of Philadelphia on Comcast. I tried to access
internet at around 9:30 and some sites would resolve and some would
not. I tried some pings / tracerts and results were mixed. However,
when they did fail, they failed on the name resolution.
Comcast's DNS servers were not answering queries, so anything you
tried to do could not convert the host name to an IP address. My
daughter told me it wasn't working around 4:30pm PDT when she got
home, and it was still messed up when I got home around 6:30pm.
My Linux box runs a caching DNS server so I just pointed the windows boxes
at it for DNS service and that fixed them.
Whatever Comcast broke, they managed to fix around 8-9pm.
Mike Iglesias Email: firstname.lastname@example.org
University of California, Irvine phone: 949-824-6926
google for "Internet storm center". If they don't have it, it wasn't
happening. akamai.com has a good public bulletin system as well, at
least I think non-customers can get to a "health of the internet" status
I didn't get any notices, so if it happened, it wasn't big enough to
trigger anything big.
Excellent advice, Dave. Thanks! I googled "internet storm center";
came up with lots of hits, and then came across a page that directed me
to http://isc.sans.org /. THAT mentioned the Comcast "problem". They
say the issue is due to an "upgrade". Thanks for the search criteria
that brought up the applicable link.
Dave Hinz wrote:
That's the right link, couldn't think of it at the time. I get
bulletins from some of our security and infrastructure providers
on big events, and didn't get one for this one.
The Sans site is a good one for doing a quick "OK, we're seeing strange
things, is it just us or is there something going on". Was the first
thing I checked a few years ago when, suddenly, during the day, our
webserver traffic cut to a third of what it had been and what was
expected. Seems someone had pulled the plug on the east coast.
Hate it when _that_ happens.
I am not aware of any outage, nor is there any report of one on Google
news. I am not involved in the day to day operations of DNS but I am
usually informed of any major Internet outage as soon as it happens,
particularly if it is a DNS issue since I am curently investigating
criminal schemes that make use of the DNS.
It looks to me as if it was a comcast only event.
Thanks to all for the confirmation that "something" was happening on the
net to Comcast users in various areas. Today I had a bit more of the
same, but only for moments at a time. I've seen my speed back up to the
usual 2-3Mb/s. Comcast offered to send a truck out to my house today,
but I declined when I learned that they officially declared an ongoing
problem in the Cupertino area just north of me that matched the type of
connectivity issue I've been having since late yesterday.
Sounds like they don't know what they're talking about, *or* they didn't
understand your problem.
DNS problems will affect _starting_ a connection. *only*.
Once the connection is established, DNS does not enter the picture.
I agree with Robert. It's not DNS. Probably just the amount of
traffic. That can be caused in a number of ways.
If you're ever interested in how the Internet as a whole is doing, go
here: http://www.internettrafficreport.com/main.htm It can be a good
indication if there are issues. Remember that if a major router is
down, traffic usually gets shuffled off somewhere else & that can lead
to delays. Sometimes it's as simple as your signal hitting a critical
number of hops; more than 15 and you generally start to notice it
(actually, it's an accumulation of time between hops & a couple of slow
hops can make 6 or 8 too many). Other times, it's just that too much
traffic gets re-routed to other major points. That sort of thing has
been getting to be less of a problem over the years as the hardware
gets 'smarter', but can still be a pain if the point is big enough.
A couple of years back, someone dug up one of the major fiber feeds
near Chicago. We had issues with our sites in California (we're east
coast US) for several days solid & then intermittently for weeks.
Aquisitions are a major source of delays, too. When Algx bought IDS
(?), they changed all the routing schemes on the old network. We had
issues for several days before things settled down & the tables all
sync'd up. Usually, you don't get a delay due to this, just 404's, but
delays can be part of it.
Major events can also clog the connections - so blaming it on the Pope
might not be too outrageous. Residential Comcast customers usually
notice a 3pm slow down. That's when all the kids get home from school
& suddenly hit the network.
That's exactly the problem I'm having now. In the afternoon, the speed
drops from 2,500+ to around 300 - 1,100. Last night a comcast rep
checked from his end to my cable modem and found great ping times UNTIL
reaching my modem. This morning I got 2700+. I'm not very optimistic
that the service call today will uncover anything wrong at my house. It
will be just like when you take your car to the mechanic; nothing will
I guess all those commercials a while back depicting neighbors
complaining about each other hogging bandwidth are true, despite
Comcast's protestations to the contrary. Why don't I believe them? :)
FINALLY the Comcast problem is out in the open. Plenty of newstories
today about the slowdown. 2 guys from comcast showed up at my house at
7:30 last night to see how my connection was doing. It was the first
weeknight that it had worked well since a week ago Tuesday. They said
that at 3:30 AM (Thursday) their Denver facility had sent an email out
that DNS issues had been solved. So here I sit with a decent
connection. My fingers are crossed. (and my DNS settings are changed <g>)
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