Checking if the computer is online

[Mickel Grönroos]

Hi all,

I have a silly question. Is there are simple way to check if the computer
is connected to the Internet? It seems this should be a pretty
straight-forward thing to do, but as I am totally unfamiliar with sockets
and such, I ask for your help before getting my hands dirty.

Cheers,

Mickel G.

--
Mickel Grönroos, application specialist, linguistics, Research support,CSC
PL 405 (Tekniikantie 15 a D), 02101 Espoo, Finland, phone [phone]
CSC is the Finnish IT center for science, www.csc.fi

[Max M]

> On Thu, 18 Sep 2003, Thomas Bellman wrote:

Or perhaps you should tell us *why* you believe you need to check
if the computer is connected to the Internet or not. Then we can
go directly to telling you that it is a bad idea, and suggest what
you should do instead. <0.5 wink>

*I* would like to use it to run a service in the background on my
Windows machine checking the machines ip adress perhaps once an hour,
and if it was different than it is supposed to be, it should send an
email to my mail adress containing the time and the ip adress.

That should make it possible to make a stolen computer "phone home" with
enough data to track it down.

But if it tries to call up on a modem, it has sort of given itself up.
An the new "owner" might get suspicious.
regards Max M

[Pierre Quentel]

Have you tried :
socket.gethostb yname(socket.ge thostname())
or
socket.gethostb yname_ex(socket .getfqdn())[2]

Normally the result should be different if you're connected or not

Cheers,
Pierre

"Mickel Grönroos" <mi****@csc.f i> a écrit dans le message de
news:ma******** *************** **********@pyth on.org...
On Thu, 18 Sep 2003, Thomas Bellman wrote:

Mickel Grönroos <mi****@csc.f i> wrote:

Hi all,

I have a silly question. Is there are simple way to check if the computer is connected to the Internet? It seems this should be a pretty
straight-forward thing to do, but as I am totally unfamiliar with sockets and such, I ask for your help before getting my hands dirty.

First of all you need to define what "being online" means...

[...] Or perhaps you should tell us *why* you believe you need to check
if the computer is connected to the Internet or not. Then we can
go directly to telling you that it is a bad idea, and suggest what
you should do instead. <0.5 wink>

OK, here's what I want to do:

When the Tkinter application I am writing starts up, it checks if certain
files on the web exists and if so, it downloads them to a local directory
replacing possible earlier copies of these files. So, what I mean by
checking if the computer is online is that I want to check if I can access
these certain remote files with urllib.urlretri eve(). If I can, then I
download them. If I can't, I assume the computer is not connected to the
Internet and I skip the update phase.

The problem with just running urllib.urlretri eve() is that the execution
of the script halts as there is no timeout available for Python 2.2.2. (I
tried timeoutsocket.p y to get this done, but that only worked on Windows
2000, not Redhat Linux 7.0. I also tried upgrading to Python 2.3, but that
caused some other problems, especially with the gettext module and with
the fact that my ISO-8859-1 encoded files needed a "coding" line.)

So that's that. Anybody still got a few lines of code that would get this
done on Python 2.2.2 on Windows _and_ Linux?

Cheers,

/Mickel G.

--
Mickel Grönroos, application specialist, linguistics, Research support, CSC
PL 405 (Tekniikantie 15 a D), 02101 Espoo, Finland, phone [phone]
CSC is the Finnish IT center for science, www.csc.fi

[Pierre Quentel]

Have you tried :
socket.gethostb yname(socket.ge thostname())
or
socket.gethostb yname_ex(socket .getfqdn())[2]

Normally the result should be different if you're connected or not

Cheers,
Pierre

"Mickel Grönroos" <mi****@csc.f i> a écrit dans le message de
news:ma******** *************** **********@pyth on.org...
On Thu, 18 Sep 2003, Thomas Bellman wrote:

Mickel Grönroos <mi****@csc.f i> wrote:

Hi all,

I have a silly question. Is there are simple way to check if the computer is connected to the Internet? It seems this should be a pretty
straight-forward thing to do, but as I am totally unfamiliar with sockets and such, I ask for your help before getting my hands dirty.

First of all you need to define what "being online" means...

[...] Or perhaps you should tell us *why* you believe you need to check
if the computer is connected to the Internet or not. Then we can
go directly to telling you that it is a bad idea, and suggest what
you should do instead. <0.5 wink>

OK, here's what I want to do:

When the Tkinter application I am writing starts up, it checks if certain
files on the web exists and if so, it downloads them to a local directory
replacing possible earlier copies of these files. So, what I mean by
checking if the computer is online is that I want to check if I can access
these certain remote files with urllib.urlretri eve(). If I can, then I
download them. If I can't, I assume the computer is not connected to the
Internet and I skip the update phase.

The problem with just running urllib.urlretri eve() is that the execution
of the script halts as there is no timeout available for Python 2.2.2. (I
tried timeoutsocket.p y to get this done, but that only worked on Windows
2000, not Redhat Linux 7.0. I also tried upgrading to Python 2.3, but that
caused some other problems, especially with the gettext module and with
the fact that my ISO-8859-1 encoded files needed a "coding" line.)

So that's that. Anybody still got a few lines of code that would get this
done on Python 2.2.2 on Windows _and_ Linux?

Cheers,

/Mickel G.

--
Mickel Grönroos, application specialist, linguistics, Research support, CSC
PL 405 (Tekniikantie 15 a D), 02101 Espoo, Finland, phone [phone]
CSC is the Finnish IT center for science, www.csc.fi

[Mickel Grönroos]

On Wed, 24 Sep 2003, Pierre Quentel wrote:

Have you tried :
socket.gethostb yname(socket.ge thostname())
or
socket.gethostb yname_ex(socket .getfqdn())[2]

Normally the result should be different if you're connected or not

Thanks for the tip! I tried this and the second line freezes execution
when I have unplugged my Ethernet cable. So again, I need a timeout on my
socket. This is not available in Python 2.2.2. I reckon I need to try
Python 2.3.

/Mickel G

[Mickel Grönroos]

On Wed, 24 Sep 2003, Pierre Quentel wrote:

Have you tried :
socket.gethostb yname(socket.ge thostname())
or
socket.gethostb yname_ex(socket .getfqdn())[2]

Normally the result should be different if you're connected or not

Thanks for the tip! I tried this and the second line freezes execution
when I have unplugged my Ethernet cable. So again, I need a timeout on my
socket. This is not available in Python 2.2.2. I reckon I need to try
Python 2.3.

/Mickel G