Help me understand this AU East bandwidth charge for VM in Southeast Asia

Question

All my resources are in Southeast Asia but last month I have 600$ charge of bandwidth for single app server. Can anyone help me understand this?

Answer 1

Linh Trieu - Although your application resources are intended to be in Southeast Asia, the cost breakdown clearly shows that the bandwidth charge (~$612) is associated with a Virtual Machine located in Australia East (AU East), and the meter used is:

• Service is Bandwidth
• Meter shows Standard Data Transfer Out
• Routing Preference is MGN

This indicates that outbound data transfer (egress) occurred from a VM in AU East, which is billable, regardless of where other resources are hosted.

Key points to help the user understand the charge

Bandwidth (Data Transfer Out) is charged per region

• Any data leaving Azure from a VM to the internet or another region is billed.
• Charges apply even if the VM is used temporarily or unintentionally. Region mismatch
• The VM incurring the cost is not in Southeast Asia, but in AU East. - Cross‑region traffic (AU East → Southeast Asia or Internet) can quickly become expensive.

1. Common reasons this happens
   • A VM was: Created temporarily (testing, migration, backup, DR, MGN replication) & Left running unintentionally.
2. High outbound traffic due to:

• Public downloads/uploads
  • Backup/export jobs
  • Replication or migration traffic
  • Application logs, media, or API responses sent to internet users

What we can suggest the user to do next (Actionable steps)

Review Azure Cost Management > Cost analysis

• Filter by: Service = Bandwidth & Resource = the AU East VM

Check VM metrics:

• Network Out Total & Verify if Azure Migrate (MGN), backups, or replication was enabled last month.

Preventive recommendations:

• Ensure all app and dependent resources are in the same region.
• Avoid exposing VMs directly to the internet if not required.
• Use: Azure CDN / Front Door for public traffic and Private Endpoints / VNet peering (same region) where possible
• Configure: Azure Budgets & cost alerts & NSG rules to restrict unnecessary outbound traffic

If the above answer helped, please do not forget to "Accept Answer" as this may help other community members to refer the info if facing a similar issue. Your contribution to the Microsoft Q&A community is highly appreciated.