Internet slowdown

[Piyono]

In the last few days I've been experiencing a general slowdown when accessing the web through a browser, and also, perhaps during email checking and Instant Messaging, although it's most apparent when surfing.

Symptom 1: When surfing, the browser is returning "can't find requested page" errors. This happens on a regular basis. Trying the link a second time usually works
Symptom 2: Pages don't load fully. The browser will stop loading a page part-way through and report "Done" in the status bar. Again, refreshing the page corrects the problem.
Symptom 3: Browser 'lag'. When I click a link or type in a URL, the browser just sits there and 'thinks about it' before taking any action (which, usually results in either Symptom 1 or Symptom 2).

I've been trying to methodically factor out all the components but it's very hard to trace the source of the slowdown. So far I've ruled out bad cabling and ZoneAlarm.

The problem is consistent across Firefox 1.x and IE6.x.

My Sympatico DSL service had been *blazing* fast up until the problem started. I mean, I wouldn't have traded it for anything. Of course, I don't know that it's sympatico that's causing the slowdowns, but then again, I don't know that it's not.


If anyone has anything to offer I'm open to sugestions...


Piyono

 

[blakerwry]

Could be DNS failure/lag. Is your computer.router set to DHCP on that system?


I suggest you try to drop to command line and type:

c:\> [b]ipconfig /flushdns[/b]

c:\> [b]ping [url]www.yahoo.com[/b][/url]

Notice the time between hitting enter and the following line "Pinging yahoo.com [216.109.112.135] with 32 bytes of data:"


This is the time it takes your ISP's DNS server to translate a domain to an IP for your computer to connect to. this should be nearly instantaneous, or atleast under 1 second.

if it takes several then you have a slow DNS server on your ISP, manually specifying DNS to another server should correct the problem.



If resolution is instantaneous, try looking at the reply time in ms. If the value is above 150 or you have packet loss you probably are experiencing some sort of failure on the physical layer. Check connections and remove any splices/splitters, replace cables, etc.


In addition to pinging yahoo.com and other major sites, try some smaller ones like SR and SF. Remember to flush your computer's DNS cache so that you force your computer to check the DNS servers for valid info.

 

[blakerwry]

im sure you get the idea on the code.. my bold tags didn't work.. :-(

 

[Fushigi]

1. http://www.broadbandreports.com/stest for benchmarking.
2. Could be spyware.

 

[Mercutio]

Spyware is absolutely the first thing I think of with those symptoms. But it's easy enough to try a different DNS. Verizon's for example, are 4.2.2.2 - 4.2.2.4.

Thing is, you are finding pages. They just aren't completely loading. That suggests that you're getting timed out. Which suggests network congestion.

 

[Fushigi]

Thing is, you are finding pages. They just aren't completely loading. That suggests that you're getting timed out. Which suggests network congestion.

Internet Traffic Report and Netstat Live could be useful. I've also just installed FastCache DNS Caching to reduce DNS requests.

 

[mubs]

Merc, is it okay to use DNS servers that don't belong to your own ISP? I'm surprised the big guys like Verizon don't block requests coming from outside their alloted IP range.

Fushigi, thanks for the link to the DNS cache proggie. A while back I asked about this, but nobody seemed to know of a good one. I'm going to try it out!

BTW, according to the Webattack page that describes what DNS is and how caching helps (link available in the Fastcache DNS caching link that you provided), web browsers are male.

 

[Mercutio]

You can use any DNS you want. No one cares.

 

[Piyono]

Well, the problems seems to have lessened a bit, but it is still apparent.

Bakewry, I ping just fine, thanks.
Invoking 'ipconfig /flushdns', however, was not as successful: "Function failed during execution". No explanation given.

Definately no unauthorized software. I'd never be able to face my clients again if my own computer was spy/ad/mal/ware-ridden. Spybot, Adaware and AVG antivirus are kept in top form and exercised regularly.

My cabling is immaculate, if I do say so myself.

I ran a few download benchmarks at Toast.net and my performance is as good or better than their fastest reference. Again, my problem is not raw speed but *lag*. I also ran the tests at the site Fushigi recommended and my connection clocked 2370mbps down and 650mbps up. What caught my attention, though, is that durring each leg of the downstream speed test, the download 'hicupped' for a split second; that is, the progress bar stopped moving for an instant and then kicked in again. This could be normal but it seems sort of indicative of my problem.

I've been using the fine network monitoring tools from AnalogX for several years, thanks Fushigi.

]-[

 

[Piyono]

Can someone tell me why I get this message when I try to execute ipconfig /flushdns:

"Could not flush the DNS Resolver Cacher: Function failed during execution."

?



Piyono