Well, that was even more fun

[ksmith]

My wireless stopped working around 730 this evening. The daily back-up had just started, and got stuck in "pending" mode for too long. I stopped it, then tried to connect to a couple of sites. Nothing.

I initially assumed that my wireless router had gone south like it did last year, especially given that I had not done any of the recommended PM (shutdown/start-up 2x a month, and a hard reset once a year). So I did a soft reset. No go. A hard reset. Nope. Another hard reset. Nope. All this along with sequential shutdown/start-up of the cable modem, the router, and my MacBook.

It didn't occur to me that anything was wrong with the cable modem given that the phone worked--I have a landline with VOI--and all the pertinent lights were on. But after another hard reset of the router failed to resolve the issue, I called Comcast. Got a recording that things were slow due to high call volumes and yes, they knew about the high speed internet issues and they were working to resolve. So. It wasn't my router after all.

Well, I'm back online now, four hours later. And I now know how to reset my router. And I already performed the annual hard reset, so that's out of the way. I'd been putting it off because I didn't want to risk losing connectivity in case I screwed up. Turns out that it wasn't that big a deal.

Comments

[mithriltabby]

Would you like to know the incantations for diagnosing that sort of thing?

[e-moon60.livejournal.com]

I certainly would!

[mithriltabby]

OK, here are the barbarous names.

[kristine-smith.livejournal.com]

You mean, other than "Hit or miss"?

If there had been a way that I could have determined what was the issue w/o having to reset things, yes, that would be good. I had tried to hook up the MacBook via the hardwire connection, and it didn't work. That perhaps should have pointed to the cable modem as the culprit, but I had seen times before when the MacBook wouldn't respond to a hardwire connection. I thought this was because I didn't have the settings for such a connection set up in my particular network account. But then I thought that a hardwire hookup should work automatically.

IOW, yes, please.

[mithriltabby]

OK, here goes— please let me know if you want me to expand on any of this:

The tool you want is named traceroute. It’s a standard command on Unix systems (and all modern Macintoshes are Unix— here’s how to run it from a shell), it’s tracert.exe on Windows, and it’s often an available option in various utilities for working with the network.

When you communicate over the Internet, the transport layer of the software takes what looks like an entire stream of data (e.g. an entire web page) and breaks it up into small packets, which are individually passed from one machine to another and another until they finally reach their destination and are reassembled. traceroute will tell you all the hops between your machine and another one you specify. For instance, here’s an abbreviated one from my desktop machine:

tempest% traceroute kristine-smith.livejournal.com
traceroute to kristine-smith.livejournal.com (208.93.0.128), 30 hops max, 60 byte packets
 1  192.168.16.1 (192.168.16.1)  4.724 ms  5.067 ms  5.128 ms
 2  router.electric-cloud.com (74.85.3.81)  4.314 ms  4.324 ms  7.792 ms
 3  noname.telekenex.com (74.85.3.245)  7.900 ms  7.903 ms  7.890 ms
...
 5  ae5-122.edge8.SanJose1.Level3.net (4.53.30.125)  10.683 ms  11.029 ms  11.162 ms
...
13  VISION-NET.car1.Chicago1.Level3.net (4.71.246.2)  88.568 ms  88.671 ms  89.369 ms
14  76-75-56-243.vnet-inc.com (76.75.56.243)  69.428 ms  70.530 ms  73.620 ms
15  livejournal.com (208.93.0.128)  73.694 ms  75.756 ms  75.880 ms

The most important thing for diagnosing your connection is the first two. The first one should be your home router, and will very likely have the IP address 192.168.1.1. If you’re getting a report from there, your connection to your router is fine. The second one (for you— my example is from a larger corporate network and the equivalent for me is #3) should belong to your ISP, and if the router is responding and the ISP isn’t, then the problem is upstream of your cable modem and it’s time to contact your ISP. If you can see your own ISP but things stall outside it (for me at work, that would be if I saw the packets from telkenex.com but not Level3.Net), their network connection is the one in trouble.

Depending on your configuration, you might have cable modem that is also your router, or a separate cable modem and router; if the latter, and you plug your machine directly into the cable modem, then you won’t have the 192.16.1.1 hop and the very first line will be the one for your ISP. However, doing that might require all kinds of complicated setup being applied to your machine’s networking configuration. (At home, I just specify the IP address and default gateway, but at my mother’s, I have to set up this thing called “PPP over Ethernet” that is a much bigger hassle.)

[kristine-smith.livejournal.com]

Thanks for this. It would have saved me a temper flare, even though the router needed to be reset anyway.

I use an Airport Extreme Base Station, which is hooked up to the cable modem. Trying to set up a hardwire connection is indeed a hassle, although I can eventually hook up the MacBook. I can't make the hardwire hook-up work with my day job laptop, though, and I don't have the admin privileges necessary to make things work. I need a wireless connection.

As it turned out, the problem was Comcast's DNS system/server/whatever.

[mithriltabby]

Having DNS go offline leads to other interesting symptoms. The command for looking up addresses used to be nslookup on most Unix systems, now it’s host or dig. A little googling suggests that there’s a Network Utility on the Mac that can do those lookups. The trick with diagnosing a DNS failure is that your own machine will often have addresses cached, so looking up something you visit a lot might seem to be working while other names don’t resolve, so it’s best to think of something you only visit occasionally when you do a query in order to detect if DNS is broken.

If it happens a lot, you could jot down the IP addresses for OpenDNS and plug those into your networking configuration when your ISP’s servers fail, but I find overall network connectivity problems to be much more common than “both of my ISP’s name servers are offline”.

[e-moon60.livejournal.com]

Thanks. I have the common ISP/telco <--> DSL modem <--> router <--> computer arrangement. So this helps.

[cabri729.livejournal.com]

When I have a problem like that I always turn on my SMS tweets which don't rely on the interwebs. It's a better back-up than a 3rd party app which will go down with the interwebs, and I have enough local people set for SMS that I found out pretty quick it was Comcrap.

[kristine-smith.livejournal.com]

Apparently it was a multistate outage involving the DNS servers. Some folks are still without service. In the comments section, folks were posting tips on how to get around this by switching to Google Free DNS or other providers. I don't know if I would have tried to do that or not.

To be honest, Comcast service hasn't been too bad for me. This is the first major internet outage I can recall in 3 1/2 years. It's still furlongs better than AT&T DSL, which kicked off every time a cloud drifted over southern Wisconsin. It was more sensitive to weather issues than my late unlamented DirecTV service.