Convert from network name to ip address

[Roidy]

I have a function that reads a file but fails if I pass it a network device
name instead of an ip address eg:-

ReadFunction("\\NAS\Myfolder\Myfile.txt") <--- Fails
ReadFunction("\\192.168.2.2\Myfolder\Myfile.txt") <--- Works

So how do I convert a network devices name to it's ip address?
ie. Convert \\NAS\ to \\192.168.2.2\

Thanks
Robert

 

[Armin Zingler]

Am 31.05.2010 14:56, schrieb Roidy:

I have a function that reads a file but fails if I pass it a network device
name instead of an ip address eg:-

ReadFunction("\\NAS\Myfolder\Myfile.txt") <--- Fails
ReadFunction("\\192.168.2.2\Myfolder\Myfile.txt") <--- Works

So how do I convert a network devices name to it's ip address?
ie. Convert \\NAS\ to \\192.168.2.2\

Try this: (passing "NAS")

System.Net.Dns.GetHostByName(ByVal String) As System.Net.IPHostEntry

Does it fail, too?

 

[Roidy]

Thanks Armin,

VB complains that GetHostByName is obsolete and tells you to use
GetHostEntry, which works perfectly:-

Dim hostname As System.Net.IPHostEntry = System.Net.Dns.GetHostEntry("NAS")
Dim ipaddress() As System.Net.IPAddress = hostname.AddressList

Now it just an easy task to write a function to strip out the network device
name from the path and replace it with the resulting IP address.

Thanks
Robert

 

[Roidy]

This is what I knocked together to check the path to see if it's network
path and then replace the device name with it's IP address. Seems to work,
can you see any problems I might face using this? or is there a better way?

Public Function PathFixer(ByVal path As String) As String
If path.StartsWith("\\") Then ' Check to see if it's a network path
Dim output As String
Dim splits() As String = path.Substring(2, path.Length -
2).Split("\")
Dim hostname As System.Net.IPHostEntry =
System.Net.Dns.GetHostEntry(splits(0))
Dim ips() As System.Net.IPAddress = hostname.AddressList
output = path.Remove(2, splits(0).Length)
Return output.Insert(2, ips(0).ToString)
Else
Return path
End If
End Function

Thanks
Robert

Thanks Armin,

VB complains that GetHostByName is obsolete and tells you to use
GetHostEntry, which works perfectly:-

Dim hostname As System.Net.IPHostEntry =
System.Net.Dns.GetHostEntry("NAS")
Dim ipaddress() As System.Net.IPAddress = hostname.AddressList

Now it just an easy task to write a function to strip out the network
device name from the path and replace it with the resulting IP address.

Thanks
Robert

 

[Armin Zingler]

Am 31.05.2010 17:55, schrieb Roidy:

Thanks Armin,

VB complains that GetHostByName is obsolete and tells you to use
GetHostEntry, which works perfectly:-

Dim hostname As System.Net.IPHostEntry = System.Net.Dns.GetHostEntry("NAS")
Dim ipaddress() As System.Net.IPAddress = hostname.AddressList

Now it just an easy task to write a function to strip out the network device
name from the path and replace it with the resulting IP address.

Yes, sorry, you're right. Didn't try it and didn't see the warning.

 

[Armin Zingler]

Am 31.05.2010 18:18, schrieb Roidy:

This is what I knocked together to check the path to see if it's network
path and then replace the device name with it's IP address. Seems to work,
can you see any problems I might face using this? or is there a better way?

If it works fine for you, it's ok. Though I wonder why your "ReadFunction"
works with the IP but not with the host name, while resolving the host name
before using GetHostEntry seems to work. What does 'ReadFunction" do with
the string? Apart from this:

- A possible problem is that the host name can not be resolved. I can't test
the situation because my provider seems to redirect all unknown host names to
the same IP.
- always enable Option Strict
- make the function Shared

 

[Roidy]

Unfortunately the readfunction isn't mine it's the MP4Read function from
libmp4v2.dll so I'm not sure why it only works with IP addresses and not
host names. Your right I should really do some error checking because if
GetHostEntry fails to resolve the host name it throws an exception.

Thanks
Robert