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Non-internet application wants to connect over internet


Non-internet application wants to connect over internet Tom Dacon
8/25/2004 6:17:31 PM
dotnet clr:
I have a little desktop application (it happens to be a Windows Forms analog
clock) that's written in VB.Net (2003). I placed a shortcut in my Startup
program group to start it up when I log on. I have put no code in the
application whatsoever to do internet communications, and yet when it starts
up at logon I've begun getting notification dialogs from my software
firewall that the app wants to connect to the internet. It doesn't happen
when the app has been freshly rebuilt, but after a few days or so it starts
to try to connect and thereafter tries again each time the app is started
up.

Thinking that I might have acquired some new kind of virus that attaches
itself to .Net executables, I made a note of the file size and the 'last
modified' date after a fresh build, and then checked it again after the
executable started wanting to connect to the internet. No changes. Norton
AntiVirus 2003 with the most recent updates shows a clean scan. I always
tell the firewall (Norton Personal Firewall 2003) to block the
communication, and the application continues to execute normally.

Has anyone else seen similar behavior in non-communications-enabled
applications, or know of anything that might shed some light on this
behavior?

Thanks,
Tom Dacon
Dacon Software Consulting


Re: Non-internet application wants to connect over internet Tom Dacon
8/25/2004 9:35:52 PM
A good point, and one that didn't occur to me, but in this case there's no
third-party component being used in the application. It's based on some
sample code from Microsoft - I don't remember exactly where I got it; maybe
it was a framework sample or something, and it's all just plain vanilla
VB.Net and framework classes.

However, I've modified it to use the Microsoft Office 11 Object Library
(Office 2003), in order to interrogate the user's (my) Outlook appointments
calendar. Periodically I get the appointments from Office and display on the
clock face little icons that represent the starting time of the
appointments, with tooltips that display the details. I suppose it's
remotely possible that somehow I'm 'waking up' Outlook, and it's going out
to try to download email, but it sounds pretty unlikely.

And of course, as you say, none of this explains why it starts behaving this
way only after the passage of some time.

A puzzle.

Thanks for your comments.

Tom Dacon
Dacon Software Consulting

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Re: Non-internet application wants to connect over internet Wayne P.
8/25/2004 11:53:19 PM
Tom,

I really don't know for sure, but this is the first thing that comes to
mind. Did you use any 3rd party components when writing your clock app? I
have heard of some 3rd party components calling home for license
verification when on the development machine. If you used a 3rd party
component, and ran the program on the development machine (even outside the
IDE), the development license could be found on the machine and applied,
thus wanting the internet. The only way to be sure is to contact the vendor
and hope they don't lie.

Although if you haven't used any 3rd party components, then obviously the
above is not the case. And if you did - it does not explain why your app
only starts this strange behaviour a few days later....

Wayne P.


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Re: Non-internet application wants to connect over internet Wayne P.
8/26/2004 1:18:07 AM
Tom,

I'm not an Office / Outlook / VBA expert - but your thought on the email
gave me an idea - is your calendar setup via an Exchange server at all?
Perhaps the query of calendar items is causing this. I'm thinking that some
of the calendar items may be cached, but a few days later the cache expires
or new appointments are made that need downloaded, thus wanting a remote
connection (internet) to the exchange server.

Of course, this is all pure speculation. I don't know - hopefully someone
else will chime in....

Good luck!

Wayne P.

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Re: Non-internet application wants to connect over internet Tom Dacon
8/27/2004 1:21:36 PM
Tracecert...OK, I'll go find about that tool and see what it shows me.

Thanks,
Tom Dacon

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Re: Non-internet application wants to connect over internet Ignacio Machin ( .NET/ C# MVP )
8/27/2004 4:01:46 PM
Hi,

Where its trying to connect?

If it's an IP do a tracert and see if you determine where it goes.

cheers,

--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation


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RE: Non-internet application wants to connect over internet rbyers NO[at]SPAM online.microsoft.com (
8/31/2004 5:04:58 PM
I don't know how Norton Personal Firewall works, but it seems likely that
it would block the network request until you choose to permit or deny the
access. In that case, you should just be able to attach a debugger while
Norton is waiting for a response from you and look through the threads
until you find one thats trying to do some network access. The call statck
should indicate who is responsible. The network access could be from
managed or unmanaged code, so if you don't see it when doing managed-only
debugging, you should try either interop debugging (managed + native in
VStudio), or native only debugging.

If Norton causes the network request to just fail (instead of waiting for a
allow/deny response from you - this seems unlikely to me), then you may not
see any threads doing any network access when you attach. You could still
set breakpoints at common networking functions (eg. WSAConnect), and wait
for them to be hit.

Rick

--
This posting is provided "AS IS" with no warranties, and confers no rights.
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