In the event you need to change your email provider, or more specifically you are looking to change your public MX record then you need to confirm that the new solution works well, and for this I would highly recommend you buy of use a test domain so you can test these changes.
Then in this "test" domain you can make the MX record the same, test your internal and external routing updates then switch you "test" domain MX record to see how the non-live performs, each ease will be different, but for argument sake lets say we are moving from mail provider to another in the form of a "Secure Access Gateway" or SEG.
When you do to move your live MX records ensure you drop the TTL down low so that if you need to revert you can do so with relevant ease, however remember that even with a low TTL the Internet DNS replication is far for immediate and even with a low TTL it can take up to the 96 hours (though I have never seen it take this long)
When you have you new domain setup from the current mail provider you need to setup the mail servers to allow relay and delivery from the "test" domain then you need to get some testing of mail flow, now this mail flow will not be like your Production domain levels, but it will give you an indication of how this will perform.
I have chosen the following examples:
- Test email contains a single attachment
- Test email contains two attachments
- Test email contains 10-15 attachments
- Test email contains 30-35 attachments
Mail testing with Scripting
This will test the above scenarios with a Powershell script that you can run after specifying certain parameters in the script and this will automatically test those scenarios, you need to ensure you have created a Attachments folder which the script will use to randomly add to the e-mails:
Script : MailTesting.ps1
# Email Testing Configuration Variables
$smtpConfig = @{
Server = "smtprelay.bear.local"
Port = 25
UseSSL = $true # Toggle SSL on/off
}
# Target mailboxes for testing
$targetMailboxes = @(
"mailbox1@croucher.cloud",
"mailbox2@croucher.cloud"
)
# Sender configuration
$senderConfig = @{
Email = "Mail.Tester@croucher.cloud"
}
# Test configuration
$testConfig = @{
AttachmentsFolder = "C:\Quarantine\MailTestingScript\Attachments"
DelayBetweenTests = 2 # 15 seconds between tests
IterationsPerScenario = 4 # Will run each scenario 10 times
LogFile = "EmailTest_$(Get-Date -Format 'yyyyMMdd_HHmmss').log" # Added log file config
}
# Function to write to both console and log file
function Write-OutputAndLog {
param(
[string]$Message,
[string]$ForegroundColor = "White"
)
Write-Host $Message -ForegroundColor $ForegroundColor
Add-Content -Path $testConfig.LogFile -Value "$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss'): $Message"
}
# Updated original Write-ColorOutput to use new logging function
function Write-ColorOutput {
param(
[string]$Message,
[string]$ForegroundColor = "White"
)
Write-OutputAndLog -Message $Message -ForegroundColor $ForegroundColor
}
# Updated countdown function with logging
function Show-Countdown {
param(
[int]$Seconds,
[string]$Message
)
$endTime = (Get-Date).AddSeconds($Seconds)
Write-OutputAndLog -Message "$Message - Starting countdown for $Seconds seconds"
while ((Get-Date) -lt $endTime) {
$timeLeft = ($endTime - (Get-Date)).ToString("mm\:ss")
Write-Host "`r$Message - Time remaining: $timeLeft" -NoNewline
Start-Sleep -Seconds 1
}
Write-OutputAndLog -Message "$Message - Complete!"
}
# Function to get random attachments
function Get-RandomAttachments {
param(
[string]$FolderPath,
[int]$MinCount = 1,
[int]$MaxCount = 35
)
$files = Get-ChildItem -Path $FolderPath -File
if ($files.Count -eq 0) {
Write-ColorOutput "No files found in attachments folder" -ForegroundColor Yellow
return @()
}
$count = Get-Random -Minimum $MinCount -Maximum ($MaxCount + 1)
$count = [Math]::Min($count, $files.Count)
return $files | Get-Random -Count $count
}
# Updated Send-TestEmail with enhanced logging
function Send-TestEmail {
param(
[string]$RecipientEmail,
[string]$Subject,
[string]$Body,
[System.IO.FileInfo[]]$Attachments
)
try {
Write-OutputAndLog "Attempting to send email to $RecipientEmail with ${$Attachments.Count} attachments"
$msg = New-Object System.Net.Mail.MailMessage
$msg.From = $senderConfig.Email
$msg.To.Add($RecipientEmail)
$msg.Subject = $Subject
$msg.Body = $Body
foreach ($attachment in $Attachments) {
$msg.Attachments.Add([System.Net.Mail.Attachment]::new($attachment.FullName))
Write-OutputAndLog "Added attachment: $($attachment.Name)"
}
$smtp = New-Object System.Net.Mail.SmtpClient($smtpConfig.Server, $smtpConfig.Port)
$smtp.EnableSsl = $smtpConfig.UseSSL
$smtp.Send($msg)
Write-ColorOutput "Successfully sent email to $RecipientEmail" -ForegroundColor Green
return $true
}
catch {
Write-ColorOutput "Failed to send email to $RecipientEmail : $_" -ForegroundColor Red
return $false
}
finally {
if ($null -ne $msg) {
$msg.Dispose()
}
if ($null -ne $smtp) {
$smtp.Dispose()
}
}
}
# Main test execution function
function Start-EmailTestSuite {
# Initialize log file
$null = New-Item -Path $testConfig.LogFile -ItemType File -Force
Write-OutputAndLog "Starting Email Test Suite - $(Get-Date)" -ForegroundColor Cyan
# Test scenarios
$testScenarios = @(
@{
Name = "Single Attachment Test"
Subject = "Test: Single Attachment"
Body = "This email contains a single attachment."
MinAttachments = 1
MaxAttachments = 1
},
@{
Name = "Double Attachment Test"
Subject = "Test: Two Attachments"
Body = "This email contains two attachments."
MinAttachments = 2
MaxAttachments = 2
},
@{
Name = "Medium Attachment Count Test"
Subject = "Test: 10-15 Attachments"
Body = "This email contains 10-15 attachments."
MinAttachments = 10
MaxAttachments = 15
},
@{
Name = "Large Attachment Count Test"
Subject = "Test: 30-35 Attachments"
Body = "This email contains 30-35 attachments."
MinAttachments = 30
MaxAttachments = 35
}
)
# Calculate total tests
$totalTests = $targetMailboxes.Count * $testScenarios.Count * $testConfig.IterationsPerScenario
# Initialize results
$results = @{}
$testCount = 0
# Start test suite
Clear-Host
Write-ColorOutput "Email Testing Suite" -ForegroundColor Cyan
Write-ColorOutput "==================" -ForegroundColor Cyan
Write-ColorOutput "SMTP Configuration:" -ForegroundColor Yellow
Write-ColorOutput "Server: $($smtpConfig.Server)" -ForegroundColor White
Write-ColorOutput "Port: $($smtpConfig.Port)" -ForegroundColor White
Write-ColorOutput "SSL Enabled: $($smtpConfig.UseSSL)" -ForegroundColor White
Write-ColorOutput "Target Mailboxes: $($targetMailboxes.Count)" -ForegroundColor White
Write-ColorOutput "Iterations per scenario: $($testConfig.IterationsPerScenario)" -ForegroundColor White
Write-ColorOutput "Total tests to run: $totalTests" -ForegroundColor White
Write-ColorOutput "Delay Between Tests: $($testConfig.DelayBetweenTests) seconds" ForegroundColor White
Write-ColorOutput "Log File: $($testConfig.LogFile)" -ForegroundColor White
foreach ($inbox in $targetMailboxes) {
$results[$inbox] = @()
foreach ($scenario in $testScenarios) {
for ($i = 1; $i -le $testConfig.IterationsPerScenario; $i++) {
$testCount++
Write-ColorOutput "Current Test ($testCount/$totalTests):" -ForegroundColor Green
Write-ColorOutput "Scenario: $($scenario.Name) - Iteration $i of $($testConfig.IterationsPerScenario)" -ForegroundColor White
Write-ColorOutput "Target: $inbox" -ForegroundColor White
$attachments = Get-RandomAttachments -FolderPath $testConfig.AttachmentsFolder `
-MinCount $scenario.MinAttachments `
-MaxCount $scenario.MaxAttachments
$success = Send-TestEmail `
-RecipientEmail $inbox `
-Subject "$($scenario.Subject) - Test $i" `
-Body "$($scenario.Body)Test iteration: $i of $($testConfig.IterationsPerScenario)" `
-Attachments $attachments
$results[$inbox] += @{
Scenario = $scenario.Name
Iteration = $i
Success = $success
AttachmentCount = $attachments.Count
Timestamp = Get-Date
}
if ($testCount -lt $totalTests) {
Show-Countdown -Seconds $testConfig.DelayBetweenTests -Message "Waiting for next test"
}
}
}
}
# Display final results
Write-ColorOutput "Test Results Summary" -ForegroundColor Green
Write-ColorOutput "==================" -ForegroundColor Green
foreach ($inbox in $targetMailboxes) {
Write-ColorOutput "Inbox: $inbox" -ForegroundColor Cyan
$inboxResults = $results[$inbox]
if ($null -eq $inboxResults -or $inboxResults.Count -eq 0) {
Write-ColorOutput "No results recorded for this inbox" -ForegroundColor Yellow
continue
}
$successfulTests = $inboxResults | Where-Object { $_.Success -eq $true }
$successCount = if ($successfulTests) { $successfulTests.Count } else { 0 }
Write-ColorOutput "Tests passed: $successCount/$($inboxResults.Count)" -ForegroundColor White
if ($successCount -gt 0) {
$totalAttachments = ($successfulTests | ForEach-Object { $_.AttachmentCount } | Measure-Object -Sum).Sum
if ($null -ne $totalAttachments) {
$avgAttachments = [math]::Round($totalAttachments / $successCount, 1)
Write-ColorOutput "Average attachments per successful email: $avgAttachments" -ForegroundColor White
}
}
}
Write-ColorOutput "Test suite completed. Log file saved to: $($testConfig.LogFile)" -ForegroundColor Green
}
# Run the test suite
Start-EmailTestSuite
When run it should look like this:
You should then see those e-mails in the destination inbox as this is the test:
You will also get an log file that logs all the testing complete as shown below:
Then you will need to update the Send-TestEmail function to include these credentials as below:
