VB.NET

FTP Socket Buffer and Address Options

Demonstrates the SoRcvBuf, SoSndBuf, PreferIpv6, and ClientIpAddress properties.

Background: These are low-level knobs for specific situations. Larger send/receive buffers can improve throughput on high-bandwidth, high-latency links, though the defaults suit the common case. PreferIpv6 only matters when a hostname resolves to both address families, choosing which to try first. ClientIpAddress is normally left unset; set it on a multihomed host to bind the outgoing connection to a particular local interface. Change any of these only with a concrete reason.

Chilkat VB.NET Downloads

Download Chilkat for VB.NET

VB.NET

Dim success As Boolean = False

Dim ftp As New Chilkat.Ftp2

ftp.Hostname = "ftp.example.com"
ftp.Username = "myFtpLogin"

'  SoRcvBuf and SoSndBuf set the TCP socket receive/send buffer sizes.  The defaults are tuned for
'  the common case; larger values can sometimes help throughput on high-latency links.
ftp.SoRcvBuf = 4194304
ftp.SoSndBuf = 524288

'  PreferIpv6 (default False) chooses IPv6 over IPv4 when a hostname resolves to both.
ftp.PreferIpv6 = False

'  ClientIpAddress is normally left unset; set it on a multihomed host to bind the outgoing
'  connection to a specific local interface.
ftp.ClientIpAddress = "192.168.1.50"

'  Normally you would not hard-code the password in source.  You should instead obtain it
'  from an interactive prompt, environment variable, or a secrets vault.
ftp.Password = "myPassword"

success = ftp.Connect()
If (success = False) Then
    Debug.WriteLine(ftp.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Connected with custom socket options.")

success = ftp.Disconnect()
If (success = False) Then
    Debug.WriteLine(ftp.LastErrorText)
    Exit Sub
End If