[Okta Webinar] Learn how to a build a cloud-first strategyRegister Now

x
?
Solved

how to use vb.net to check if my winform application is block by firewall TCP/port

Posted on 2011-03-25
3
Medium Priority
?
1,235 Views
Last Modified: 2012-06-21
Hi
I want winform application to be aware of firewall that would block TCP and Port it is using.

Is there such code? to check if firewall is blocking?
0
Comment
Question by:JSW21
  • 2
3 Comments
 
LVL 12

Accepted Solution

by:
Hairbrush earned 2000 total points
ID: 35213960
Hi

Yes, it is possible to do this.  You will need to use the System.Net.Sockets namespace in the .NET Framework.  Try the code below:
Dim hostname As String = "server1"
Dim portno As Integer = 9081
Dim ipa As IPAddress = CType(Dns.GetHostAddresses(hostname)(0), IPAddress)
Try
	Dim sock As System.Net.Sockets.Socket = New System.Net.Sockets.Socket(System.Net.Sockets.AddressFamily.InterNetwork, System.Net.Sockets.SocketType.Stream, System.Net.Sockets.ProtocolType.Tcp)
	sock.Connect(ipa, portno)
	If sock.Connected = True Then ' Port is in use and connection is successful
			MessageBox.Show("Port is Closed")
	End If
	sock.Close()

Catch ex As System.Net.Sockets.SocketException
	If ex.ErrorCode = 10061 Then ' Port is unused and could not establish connection
		MessageBox.Show("Port is Open!")
	Else
		MessageBox.Show(ex.Message)
	End If
End Try

Open in new window

0
 

Author Closing Comment

by:JSW21
ID: 35217934
sock.close
will allow me to really connect it again later right?
0
 
LVL 12

Expert Comment

by:Hairbrush
ID: 35230399
Yes.
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

A long time ago (May 2011), I have written an article showing you how to create a DLL using Visual Studio 2005 to be hosted in SQL Server 2005. That was valid at that time and it is still valid if you are still using these versions. You can still re…
Network ports are the threads that hold network communication together. They are an essential part of networking that can be easily ignore or misunderstood, my goals is to show those who don't have a strong network foundation how network ports opera…
This Micro Tutorial will teach you how to add a cinematic look to any film or video out there. There are very few simple steps that you will follow to do so. This will be demonstrated using Adobe Premiere Pro CS6.
As many of you are aware about Scanpst.exe utility which is owned by Microsoft itself to repair inaccessible or damaged PST files, but the question is do you really think Scanpst.exe is capable to repair all sorts of PST related corruption issues?
Suggested Courses
Course of the Month19 days, 15 hours left to enroll

873 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question