Is there a utility that shows what is using internet connection?

[zollerwagner]

(Moderators: I'm not sure where to place this question. Feel free to move it.)

Sometimes I'll be working on my computer and some program will start hogging my internet connection (dialup) without (recent) permission. (I probably clicked a check box some time ago.)

It's probably MS or Norton updating my programs, but I'd like to be able to check to see what it is.

Is there a utility that does that?

[tedster]

Control-alt-delete often shows it at the top of the stack, and very quickly.

[zollerwagner]

(Thanks for moving this to a better home, Ted.)

Do you look at the processes in particular in the Windows Task Manager?

I have seen Norton there. I'll try again next time it occurs.

[lammert]

Use the command line utility netstat, which is present on almost any computer. It shows the processes, IP addresses and ports used.

[zollerwagner]

That sounds like exactly what I was looking for. Thanks!

[zollerwagner]

When I run netstat on XP Pro with the "Start > Run", it pops up a dos window then closes down before I can read it.

So I looked for help on MS [microsoft.com] and learned that I can type in: "netstat -o 5" (no quotes) to get a report every 5 seconds. That works.

Thanks again!

[diddlydazz]

hi zollerwagner

if you click START, then RUN and type cmd instead and press enter, your prompt window will then stay open and you can play around as much as you like ;o)

great find by the way: netstat -o 5

cheers

Dazz

[zollerwagner]

Ah, that's very good. Thanks.

You know, fifteen years ago any web developer (thinking in terms of "what if") would have all known this stuff. Now it feels like Greek or Latin, an ancient language!

[lammert]

fifteen years ago any web developer (thinking in terms of "what if") would have all known this stuff

Fifteen years ago there was only one web developer, Tim Berners Lee [w3.org] :) I think he knew about the netstat command ;) Only in 1993/1994 [w3.org] the web (in terms of HTTP protocol) started to penetrate the internet. Before that it was the time of FTP, Gopher and Telnet and other text oriented protocols.

The nice thing of modern computer manufacturers is that they still keep the old utilities available under their fancy OS. Utilities like netstat, lpr/lpd printing and a dozen others are available on almost all modern operating systems. When you switch platforms almost once a month for different projects--as in my situation--you start to love those old stuff. These utilities have often more power than any new utility on the market.

Maybe I will start a thread in the near future which discusses some old, but still very good networking tools.

[zollerwagner]

Yep, that's exactly why I said "what if". That would ahve been a time when the idea of a web designer was just a twinkle in Tim's eyes...if that.

And, yes, that list of old utilities still worth knowing about would be a very useful topic.

[zollerwagner]

Is there a way to find out what program is associated with the "local address" shown by netstat?

Sometimes I can tell what is going on by the foreign address, but others are more cryptic, like when I get this kind of listing:
TCP MyComputer:1148 localhost:1148 ESTABLISHED

The task manager doesn't show the process numbers.

[lammert]

According to the Microsoft netstat help page [microsoft.com] the -o displays the process ID of the connection. The task manager shows which program is associated with this PID.

As far as I know the -o option is new on Windows XP. It doesn't work on my Windows 2000 computer. You mentioned you used XP Pro so the -o option should give the information you want.

<added>
Each protocol has its own port number. The official list is at [iana.org...] Number 1148 is not mentioned there. It seems to be internally used by one of your programs.
</added>