To help prevent overwhelming network devices while pasting in large configuration files, user miked on the Van Dyke forums provided a script that you can use in SecureCRT.

Scripts

Save the appropriate script somewhere you can browse for it in later steps.

The script can also be downloaded from the aforementioned post; once downloaded, remove the .txt file extension so SecureCRT recognizes it.

  • PasteWithEchoFlowControl.vbs.txt - VBS script for Windows users.
  • PasteWithEchoFlowControl.py.txt - Python script for Linux users.
Expand for VB Script
# $language = "VBScript"
# $interface = "1.0"

' PasteWithFlowControl.vbs
'   Last Modified: 21 Mar, 2012
'
' DESCRIPTION:
'   Demonstrates how to send data from the Windows Clipboard to a remote system,
'   sending each line one at a time and waiting for prior lines to be echoed
'   back by the remote system before moving on with sending subsequent lines.
'   This is one approach to prevent overwhelming remote hosts like cisco
'   devices that don't implement any SSH flow control and therefore are
'   incapable of accepting data as fast as SecureCRT normally sends it.

crt.Screen.Synchronous = True
crt.Screen.IgnoreEscape = True

Sub Main()
    ' If there isn't an active connection, there's no point in continuing
    ' since we can't send data.
    If Not crt.Session.Connected Then
        crt.Dialog.MessageBox "Sending data requires an active connection."
        Exit Sub
    End If

    ' If there isn't anything in the Windows Clipboard, it doesn't make any
    ' sense to continue with the script.
    If Trim(crt.Clipboard.Text) = "" Then
        crt.Dialog.MessageBox "No text found in the Windows Clipboard."
        Exit Sub
    End If

    ' Keep timing information so that we can display how long it took for the
    ' data to be sent to the remote (each line sent only after the prior line
    ' was echoed back to SecureCRT, as a flow control mechanism).
    nStartTime = Timer

    ' Multiple lines in the Windows Clipboard are typically stored with a CRLF
    ' separator, but this script example tries to accommodate other line endings
    ' that might be supported by some editors. Break up lines into an array
    ' (each line as an element within the array).
    If Instr(crt.Clipboard.Text, vbcrlf) > 0 Then
        vLines = Split(crt.Clipboard.Text, vbcrlf)
    ElseIf Instr(crt.Clipboard.Text, vblf) > 0 Then
        vLines = Split(crt.Clipboard.Text, vblf)
    Else
        vLines = Split(crt.Clipboard.Text, vbcr)
    End If

    nLineNumber = 0
    For Each strLine In vLines
        ' Send the next line to the remote
        crt.Screen.Send strLine & vbcr

        ' Wait for the remote to echo the line back to SecureCRT; bail if the
        ' remote fails to echo the line back to us within 3 seconds.
        If Not crt.Screen.WaitForString(strLine, 3) Then
            crt.Dialog.MessageBox _
                "Sent " & nLineNumber + 1 & " lines, but the last one was " & _
                "not echoed back to SecureCRT within 3 seconds." & vbcrlf & _
                vbcrlf & _
                "Abandoning paste operation."
            Exit Sub
        End If
        nLineNumber = nLineNumber + 1
    Next

    ' Inform that the data has all been sent.
    crt.Dialog.MessageBox _
        nLineNumber & " lines from the clipboard have been sent." & _
        vbcrlf & vbcrlf & _
        "Time elapsed: " & GetMinutesAndSeconds(Timer - nStartTime)
End Sub

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Function GetMinutesAndSeconds(nTotalSecondsElapsed)
    Dim nMinutes, nSeconds, nMSeconds
    Dim nMinutesElapsed, nSecondsValue, nSecondsElapsed

    If nTotalSecondsElapsed = 0 Then
        GetMinutesAndSeconds = "less than a millisecond."
        Exit Function
    End If

    ' convert seconds into a fractional minutes value
    nMinutesElapsed = nTotalSecondsElapsed / 60

    ' convert the decimal portion into the number of remaining seconds
    nSecondsValue = nMinutesElapsed - Fix(nMinutesElapsed)
    nSecondsElapsed = Fix(nSecondsValue * 60)

    ' Remove the decimal from the minutes value
    nMinutesElapsed = Fix(nMinutesElapsed)

    ' Get the number of Milliseconds, Seconds, and Minutes to return to the
    ' caller byref
    nMSeconds = fix(1000 * (nTotalSecondsElapsed - Fix(nTotalSecondsElapsed)))
    nSeconds = nSecondsElapsed
    nMinutes = nMinutesElapsed

    ' Form the final string to be returned
    GetMinutesAndSeconds = nMinutesElapsed & " minutes, " & _
        nSecondsElapsed & " seconds, and " & _
        nMSeconds & " ms"
End Function
Expand for Python Script
# $language = "python"
# $interface = "1.0"

# PasteWithEchoFlowControl.py
#
# Description:
#   Demonstrates how to send a block of lines from the clipboard and
#   wait for those lines to be echoed back by the remote host before the next
#   block of lines is sent. This is one approach to prevent overwhelming a
#   remote host that cannot accept data as fast as SecureCRT normally sends it
#   by making sure the remote machine has received each block of lines before
#   moving on with the next block.

import SecureCRT
import time

crt.Screen.Synchronous = True
crt.Screen.IgnoreEscape = True

def main():
    # If there isn't an active connection, there's no point in continuing
    # since we can't send data.
    if not crt.Session.Connected:
        crt.Dialog.MessageBox("Sending data requires an active connection.")
        return
    
    # If there isn't anything in the clipboard, it doesn't make any
    # sense to continue with the script.
    if crt.Clipboard.Text.strip() == "":
        crt.Dialog.MessageBox("No text found in the clipboard.")
        return
    
    
    # Keep timing information so that we can display how long it took for the
    # data to be sent to the remote (each line sent only after the prior line
    # was echo'd back to SecureCRT, as a flow control mechanism).
    nStartTime = time.time()

    # Multiple lines in the clipboard are typically stored with a CRLF
    # separator, but this script example tries to accommodate other line endings
    # that might be supported by some editors. Break up lines into an array
    # (each line as an element within the array).
    if crt.Clipboard.Text.find("\r\n") > -1:
        vLines = crt.Clipboard.Text.split("\r\n")
    elif crt.Clipboard.Text.find("\n") > -1:
        vLines = crt.Clipboard.Text.split("\n")
    else:
        vLines = crt.Clipboard.Text.split("\r")
    
    
    nLineNumber = 0
    for strLine in vLines:
        # Send the next line to the remote
        crt.Screen.Send(strLine + "\r")
        
        bSuccess = False
        # If the current line isn't empty, wait for it to be echo'd back to us
        if not strLine == "":
            # Wait for the remote to echo the line back to SecureCRT; bail if
            # the remote fails to echo the line back to us within 3 seconds.
            bSuccess = crt.Screen.WaitForString(strLine, 3)
        else:
            crt.Session.SetStatusText(
                "Sent a blank line; waiting for cursor to move...")
            bSuccess = crt.Screen.WaitForCursor(3)
            crt.Session.SetStatusText("")
        
        if not bSuccess:
            crt.Dialog.MessageBox(
                "Sent %d lines, but the most recent line sent " % (nLineNumber + 1) +
                "was not echoed back to SecureCRT within 3 seconds.\r\n\r\n" +
                "Abandoning paste operation.")
            return

        nLineNumber += 1
    
    # Calculate seconds elapsed
    nTimeElapsed = time.time() - nStartTime
    
    # Inform that the data has all been sent.
    crt.Dialog.MessageBox(
        "%d lines from the clipboard have been sent.\r\n\r\n" % (nLineNumber) + 
        "Time elapsed: %2.3f seconds." % (nTimeElapsed))

main()

SecureCRT Configuration

Perform the following steps to add the button...

How to create the button in SecureCRT
In SecureCRT menus, select View > Button Bar.
menu-buttonbar
Right click on the button bar (bottom of window) and select New Button.
newbutton
A Map Button window will appear; in the Function menu, choose Run Script.
mapbutton
Enter a label to describe the button (ie. Echo Flow Control Paste), click the to browse to wherever you have the script file saved.
mapbutton2
Click OK, and the new button will be in the button bar.
buttondone

Now when the button is hit the script will run and paste the clipboard contents, waiting for each line to be echo’ed before sending the next line.