How to fix Nat Getway

Kwadjossan KPAKPAVI 20 Reputation points
2025-08-22T05:52:16.05+00:00

Hey guys. My NAT getaway had been consuming my Azure resource. Is there any best option besides that?

I haven't use Azure for 1 or 2 weeks, but when I connected back, my Nat getaway had a high fee, Why

?

Azure NAT Gateway
Azure NAT Gateway

NAT Gateway is a fully managed service that securely routes internet traffic from a private virtual network with enterprise-grade performance and low latency.

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Michele Ariis 7,315 Reputation points MVP Volunteer Moderator
2025-08-22T06:11:56.35+00:00

Hi, NAT Gateway charges even when “idle.” You pay a fixed hourly fee per NAT GW (partial hours bill as full) plus data processed (outbound + return); if the NAT GW still exists and is attached to a subnet, the meter keeps running, also, any background egress (VM updates, AKS image pulls, agents) will add data charges. And once a NAT GW is on a subnet it takes precedence over LB outbound/IPs, so all egress in that subnet flows (and bills) through it.

What to do (cheapest first):

-Delete the NAT Gateway (and its Public IPs/prefix) when you don’t need internet egress; there’s no “stop” state, only deletion stops the hourly meter. Recreate later via IaC. Then put workloads that must egress on a separate subnet you can attach a NAT GW to only when needed.

-For small/dev workloads, use Standard Load Balancer outbound rules or an instance public IP on just the VM(s) that need egress; both are usually cheaper at low volume (you’ll still pay bandwidth, but no NAT GW hourly).

-Right-size & limit traffic: keep only the needed number of Public IPs on the NAT GW, move chatty services off that subnet, and reduce background egress (AKS pulls from ACR in-region/private link, OS updates via WSUS/repo mirror).

-Verify what’s driving cost: in Cost analysis filter by NAT Gateway meters (Hours vs Data processed); in Metrics check SNAT Connection Count / Total SNAT Connection Count and bytes to see if something kept talking while you were away; for deeper visibility turn on VNet flow logs for the subnet.

Rule of thumb: keep NAT Gateway for scale/stable egress; otherwise prefer LB outbound or per-VM public IP and only enable NAT GW on subnets that truly need it.

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  1. Anonymous
    2025-08-22T07:38:19.3433333+00:00

    Hi Kwadjossan KPAKPAVI,

    Thank you for reaching out on Microsoft Q&A forum

    To understand why Nat getaway had a high fee & to follow the best practices for budget friendly, please follow the below points.

    Fixed hourly cost

    NAT Gateways come with a fixed hourly cost as long as they're provisioned even if no traffic is passing through them. So, simply having one running (even unused) will continue to add up on your bill.

    Data Processing Fees

    In addition to the hourly fee, you'll also be charged for the amount of data processed both outgoing and incoming. This can happen quietly in the background, even if you’re not actively using the virtual machines.

    Cost-Saving steps

    Delete the NAT Gateway (When Not in Use)

    If you don’t currently need internet access for your VMs, the most effective way to stop charges is to delete the NAT Gateway and any attached public IP addresses, can be recreated later.

    Using Standard Load Balancer

    For smaller or low-traffic workloads, consider switching to a Standard Load Balancer with outbound rules, or simply assign public IPs directly to your VMs. This can often be a more budget-friendly alternative if you're not moving large volumes of data.

    Use analytics

    Use Azure Cost Management tools to dive into what's causing high NAT Gateway charges.

    Control Background Traffic

    Look at which services are generating background data like auto-updates or monitoring agents and limit or schedule them more efficiently to avoid unnecessary data transfers.

    Set up separate subnets for resources that need internet access and those that don’t. This will help you to save some budget.

    To understand more about NAT gateway pricing , please find the link below.

    https://azure.microsoft.com/en-us/pricing/details/azure-nat-gateway/

    If you find this comment helpful, Please “up-vote” for the information provided , this can be beneficial to community members.

    Kindly let us know if you have any additional questions.

    Thanks

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