Connection problems when attempting outbound connections from EFT Server using SFTP


THE INFORMATION IN THIS ARTICLE APPLIES TO:

  • EFT Server, v6.4.0 and later

EFT v8.0 and later store Advanced Properties in a JSON file. When you upgrade from EFT v7.4.x to EFT v8, the non-default settings that you have defined in the registry will be added to the Advanced Properties file during upgrade. (Default settings become part of the EFT configuration files.) For a more on how to use advanced properties, and a spreadsheet of the advanced properties, please refer to the "Advanced Properties" topic in the help for your version of EFT. 

SYMPTOM

Connection problems when attempting outbound connections from EFT Server using SFTP.

MORE INFORMATION

If a client (EFT Server) sends the SSH version message too quickly, some SSH (SFTP) servers get their state machine confused, and they advance to the KEX INIT message even though they have not yet sent their SSH version message. When viewing the connection via Wire Shark, you don't see an SSH Version message from the remote SFTP server. Instead you see EFT Server connect and then immediately send its SSH version message. The remote server then replies with KEX INIT instead of SSH version. The radvanced properites below slow down the EFT Server client, causing it to wait for the server to send its SSH version message.

RESOLUTION

Create the advanced property WaitForServerVersion and specify a value:

     0 (disabled; the default) or 1 (enabled)

    Create the advanced property DelayBeforeVersionString and specify a value:

         x <= 0 (disabled; the default), x >= 1 (delay in milliseconds)

    In EFT v8 and later:

    Add the name:value pair to the AdvancedProperties.JSON file in EFT's \ProgramData\ directory as described in the "Advanced Properties" topic in the online help for your version of EFT.

    {
    "WaitForServerVersion": 1,
    "DelayBeforeVersionString": 20
    }

    In versions prior to v8.0:

    Add the DWORD values below in the following location:

    64 bit: HKEY_LOCAL_MACHINE\Software\Wow6432Node\GlobalSCAPE Inc.\EFT Server 4.0\

    32-bit: HKEY_LOCAL_MACHINE\Software\GlobalSCAPE Inc.\EFT Server 4.0\