Azure route tables: export routes by destination prefix

Overview

This PowerShell script searches every enabled Azure subscription available to the current account, inspects every route table, and exports only the routes whose destination prefix starts with a specific value.

In its current form, the filter is:

10.114.*

This is useful when you need to quickly answer questions such as:

• Which route tables contain routes for a given private range?
• Which subscription and resource group owns those routes?
• What next hop is configured for each matching prefix?

What the script does

• Retrieves enabled Azure subscriptions with Get-AzSubscription.
• Switches context into each subscription with Set-AzContext.
• Reads route tables with Get-AzRouteTable.
• Filters routes where AddressPrefix matches 10.114.*.
• Prints matches immediately to the console.
• Collects all matches into objects for sorting and CSV export.
• Writes a CSV file to the user home directory.

Prerequisites

Install the Azure PowerShell modules if needed:

Install-Module Az -Scope CurrentUser

Connect to Azure before running the script:

Connect-AzAccount

The account must have permission to read route tables in the subscriptions being checked.

Output

The CSV is written to:

$HOME/routes-10.114.csv

Each row includes:

• SubscriptionName
• SubscriptionId
• ResourceGroup
• RouteTable
• Location
• RouteName
• AddressPrefix
• NextHopType
• NextHopIpAddress

PowerShell script

$CsvPath = "$HOME/routes-10.114.csv"
 
$results = [System.Collections.Generic.List[object]]::new()
 
$subscriptions = Get-AzSubscription |
    Where-Object { $_.State -eq "Enabled" }
 
foreach ($sub in $subscriptions) {
 
    Write-Host ""
    Write-Host "Checking subscription: $($sub.Name) [$($sub.Id)]" -ForegroundColor Cyan
 
    try {
        Set-AzContext -SubscriptionId $sub.Id -ErrorAction Stop | Out-Null
 
        $routeTables = Get-AzRouteTable -ErrorAction Stop
 
        foreach ($routeTable in $routeTables) {
 
            foreach ($route in $routeTable.Routes) {
 
                if ($route.AddressPrefix -like "10.114.*") {
 
                    $result = [PSCustomObject]@{
                        SubscriptionName = $sub.Name
                        SubscriptionId   = $sub.Id
                        ResourceGroup    = $routeTable.ResourceGroupName
                        RouteTable       = $routeTable.Name
                        Location         = $routeTable.Location
                        RouteName        = $route.Name
                        AddressPrefix    = $route.AddressPrefix
                        NextHopType      = $route.NextHopType
                        NextHopIpAddress = $route.NextHopIpAddress
                    }
 
                    $results.Add($result)
 
                    Write-Host "MATCH: " -ForegroundColor Green -NoNewline
                    Write-Host "$($route.AddressPrefix) " -ForegroundColor Yellow -NoNewline
                    Write-Host "-> $($route.NextHopType)"
 
                    Write-Host "       Route Table:    $($routeTable.Name)"
                    Write-Host "       Resource Group: $($routeTable.ResourceGroupName)"
                    Write-Host "       Route:          $($route.Name)"
 
                    if ($route.NextHopIpAddress) {
                        Write-Host "       Next Hop IP:    $($route.NextHopIpAddress)"
                    }
 
                    Write-Host ""
                }
            }
        }
    }
    catch {
        Write-Warning "Failed to process subscription '$($sub.Name)': $($_.Exception.Message)"
    }
}
 
$sortedResults = $results |
    Sort-Object SubscriptionName, ResourceGroup, RouteTable, AddressPrefix
 
$sortedResults |
    Export-Csv -Path $CsvPath -NoTypeInformation
 
Write-Host ""
Write-Host "===================== RESULTS =====================" -ForegroundColor Cyan
 
if ($results.Count -gt 0) {
 
    $sortedResults |
        Format-Table `
            SubscriptionName,
            ResourceGroup,
            RouteTable,
            RouteName,
            AddressPrefix,
            NextHopType,
            NextHopIpAddress `
            -AutoSize
 
    Write-Host ""
    Write-Host "Found $($results.Count) matching routes." -ForegroundColor Green
    Write-Host "CSV exported to: $CsvPath" -ForegroundColor Green
}
else {
    Write-Host "No routes starting with 10.114. were found." -ForegroundColor Yellow
}

Notes

• The current filter uses -like "10.114.*", so it matches string prefixes rather than CIDR math.
• If you want a reusable variant, move 10.114 and $CsvPath into parameters.
• If some subscriptions fail, the script continues and prints a warning instead of stopping the full scan.