Invoke-GitHubPing.ps1

$logPath = 'D:\Temp\github-ping.log'
$title = "Script started at " + (Get-Date)
Set-Content -Value $title -Path $logPath
Write-Host -Object $title
$ip = 'Error'
$logIt = $false
$count = 0
$result = $null
$newResult = $null
$newIp = $null
$start = Get-Date -Format hh:mm:ss
$initial = $true
while ($true) {
  try {
    $resolve = Resolve-DnsName -Name github.com
    $newIp = $resolve[0].IPAddress
    if ($ip -ne $newIp) {
      $ip = $newIp
      $logIt = $true
    }

    $res = Invoke-WebRequest -Uri 'http://github.com' 
    $newResult = 'Succeeded'
  }
  catch {
    $newResult = 'Failed'
  }
  if ($result -ne $newResult) {
    $logIt = $true
    $result = $newResult
  }
  if ($logIt -and !$initial) {
    $count = 0
    $start = Get-Date -Format hh:mm:ss
    Add-Content -Value $message -Path D:\Temp\github-ping.log
  }
  $count++
  $message = "HTTP:[github.com] Start:[$start] Time:[$(Get-Date -Format hh:mm:ss)] IP:[$ip] Result:[$result] Count: [$count]"
  Write-Host -Object $message
  $initial = $false
  $newIp = $null
  $newResult = 'Failed'
  $logIt = $false
  Start-Sleep -Seconds 4
}

I had internet issues at home and this script helped me to discover the issue. GitHub was being served via three public IP addresses and only one was working. The source of the issue was the local service provider routing.