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determine if firewall is blocking my app thru vb6 code

Posted on 2010-08-13
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Last Modified: 2012-05-10
I have had an ongoing problem with my app that sends info to me using my online jmail component.
In about 100 installs  i get a runtime error 0 and my.does not even run. i have tried my solutations to no avail. How can i determine thu vb6 code if a firewall is blocking my app ?
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Question by:isnoend2001
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by:KiasChaos83
KiasChaos83 earned 250 total points
ID: 33434494
You can't really tell if a firewall is blocking your connection.

The problem is that a blocked connection has the same behaviour as a connection where the computer doesn't exist. Does that make sense? If you get blocked by a firewall, the firewall doesn't let you know that you were blocked.. it just ignores your request completely.
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CarlvanEijk earned 250 total points
ID: 33434585
You could use TCPveiw to work out what ports are being used by your app, and work backwards from there: http://technet.microsoft.com/en-us/sysinternals/bb897437.aspx

If it's the local firewall, you can identify the ports/aps and add specific tcp/udp rules. If you're supplying the application for many machines on the network you can configure the windows firewall via Group Policy
http://technet.microsoft.com/en-us/library/bb490626.aspx

Furthermore, once you've identified the ports you can apply these same rules to the enterprise firewalls, either yourself or via the local sysadmin person. The settings will be specific to the flavour of firewall, so I can;t help with specifics.

Once you've worked all that out, you could add some sort of built in post install test to check if the ports are open and popup a readme for how to resolve firewall issues......
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by:isnoend2001
ID: 33434687
Thanks guys have found it is not the firewall as the user told me his computer name. Then looking at the emails i get on first install i was able to determine that indeed i did get
an email for this user. I usually get about 20 a day with users permission telling me the users pc name os, etc and can never determine who the user is.
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by:CarlvanEijk
ID: 33435124
your bad ;)
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