Azure naming · Microsoft.Network/virtualNetworks/subnets

snet Subnet

A subnet inside a virtual network. Unique within the VNet.

Naming constraints

CAF abbreviationsnet
Resource typeMicrosoft.Network/virtualNetworks/subnets
Length1–80 characters
CaseMixed case
Allowed charactersAlphanumerics, underscores, periods, and hyphens. Start with alphanumeric; end with alphanumeric or underscore.
Uniqueness Parent resource
SeparatorHyphen
Watch out: Some services require fixed subnet names: AzureFirewallSubnet, AzureBastionSubnet, GatewaySubnet, RouteServerSubnet. Those can't follow your convention.

Source: Microsoft Learn, “Naming rules and restrictions for Azure resources”, checked October 2026. Abbreviation from the Cloud Adoption Framework.

Example & copy-ready

A worked name for workload app, env prod, region weu, instance 001.

Example name
snet-app-prod-weu-001 Valid
Validation regex for CI checks or pre-commit hooks (.NET and JavaScript) 
^(?=.{1,80}$)[A-Za-z0-9](?:[A-Za-z0-9_.-]*[A-Za-z0-9_])?$
Bicep naming expression 
var name = take('snet-${workload}-${env}-${region}-${instance}', 80)
Terraform local 
locals {
  name = substr(join("-", compact(["snet", var.workload, var.env, var.region, var.instance])), 0, 80)
}

Azure Policy can't evaluate regular expressions, so a policy can check the snet prefix but not the full format. Run the regex in your pipeline, or audit existing names on a schedule.

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Uniqueness scope

Unique within its parent resource only, for example a subnet within its virtual network or a database within its server.

Open in the name generator

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