problem where "Unexpected null reply received"

Question

The edtFTPnet change log says:

Version 1.1.6
(8 Apr 2005) Added CdUp()
Allow validation to be switched off in quote()
Tidied exception handling in Dir()
Fixed problem where "Unexpected null reply received"
Made events virtual

But I'm still getting:

INFO [AEPower.OMSCalloutHRData.FTPServices] 12 May 2005 11:30:30.961 : Connecting
DEBUG [EnterpriseDT.Net.Ftp.FTPClient] 12 May 2005 11:30:31.149 : Connecting to 63.146.167.177:21
DEBUG [AEPower.OMSCalloutHRData.FTPServices] 12 May 2005 11:30:45.275 : at EnterpriseDT.Net.Ftp.FTPControlSocket.ReadReply()
at EnterpriseDT.Net.Ftp.FTPControlSocket.Initialize(BaseSocket sock, IPAddress remoteHost, Int32 controlPort, Int32 timeout)
at EnterpriseDT.Net.Ftp.FTPControlSocket..ctor(IPAddress remoteHost, Int32 controlPort, Int32 timeout)
at EnterpriseDT.Net.Ftp.FTPClient.Connect(IPAddress remoteAddr, Int32 controlPort, Int32 timeout)
at EnterpriseDT.Net.Ftp.FTPClient..ctor(IPAddress remoteAddr, Int32 controlPort, Int32 timeout)
at EnterpriseDT.Net.Ftp.FTPClient..ctor(String remoteHost)
at AEPower.OMSCalloutHRData.FTPServices.TransferFile(String FileName)
ERROR [AEPower.OMSCalloutHRData.FTPServices] 12 May 2005 11:30:45.275 : : Unexpected null reply received
at EnterpriseDT.Net.Ftp.FTPC


General Information

Additonal Info:
ExceptionManager.MachineName: SAPASV44
ExceptionManager.TimeStamp: 5/12/2005 11:30:45 AM
ExceptionManager.FullName: Microsoft.ApplicationBlocks.ExceptionManagement, Version=1.0.1683.19009, Culture=neutral, PublicKeyToken=null
ExceptionManager.AppDomainName: OMSCalloutHRData.exe
ExceptionManager.ThreadIdentity:
ExceptionManager.WindowsIdentity: AP\Service3

Exception Information
System.SystemException: Unexpected null reply received
at EnterpriseDT.Net.Ftp.FTPControlSocket.ReadReply()
at EnterpriseDT.Net.Ftp.FTPControlSocket.Initialize(BaseSocket sock, IPAddress remoteHost, Int32 controlPort, Int32 timeout)
at EnterpriseDT.Net.Ftp.FTPControlSocket..ctor(IPAddress remoteHost, Int32 controlPort, Int32 timeout)
at EnterpriseDT.Net.Ftp.FTPClient.Connect(IPAddress remoteAddr, Int32 controlPort, Int32 timeout)
at EnterpriseDT.Net.Ftp.FTPClient..ctor(IPAddress remoteAddr, Int32 controlPort, Int32 timeout)
at EnterpriseDT.Net.Ftp.FTPClient..ctor(String remoteHost)
at AEPower.OMSCalloutHRData.FTPServices.TransferFile(String FileName)

Answer 1

It isn't impossible to get this error - the fix stopped it occurring
erroneously when blank lines were included in server replies.

For some reason your FTP server is sending a null reply to the client. It seems that the server control connection is successfully made, but when the client reads the socket no data is there.

Try connecting with a command line client with debug set to on and see what happens.