> ## Documentation Index > Fetch the complete documentation index at: https://altostrat.io/docs/llms.txt > Use this file to discover all available pages before exploring further. # Update a VPN instance > Modifies the configuration of an existing VPN instance, such as its name, DNS settings, or pushed routes. ## OpenAPI ````yaml /api/en/managed-vpn.yaml put /vpn/instances/{instanceId} openapi: 3.0.3 info: title: Altostrat Managed VPN API version: 1.0.0 description: >- Manage SDX managed VPN instances, peers, site subnets, regions, and user-facing client configuration through the public `/vpn` gateway path. servers: - url: https://v1.api.altostrat.io description: Altostrat Production API security: [] tags: - name: Instances description: Manage VPN instances, which are the core server deployments. - name: Peers description: Manage peers, which are the clients and sites connecting to an instance. - name: Utilities description: Helper endpoints for retrieving supplementary data like server regions. - name: Client Configuration description: Retrieve user-facing VPN client configuration bundles. paths: /vpn/instances/{instanceId}: put: tags: - Instances summary: Update a VPN instance description: >- Modifies the configuration of an existing VPN instance, such as its name, DNS settings, or pushed routes. operationId: updateInstance parameters: - name: instanceId in: path required: true description: The unique identifier (UUID) for the VPN instance. schema: type: string format: uuid example: d290f1ee-6c54-4b01-90e6-d701748f0851 requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/InstanceUpdate' responses: '200': description: The instance was updated successfully. content: application/json: schema: $ref: '#/components/schemas/Instance' '400': description: Bad Request - The request was malformed or invalid. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: Unauthorized. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '403': description: Forbidden - Insufficient scopes. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '404': description: The specified instance was not found. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: Internal Server Error. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' security: - BearerAuth: - vpn:update components: schemas: InstanceUpdate: type: object required: - name - pushed_routes - public_dns properties: name: type: string description: A new human-readable name for the instance. minLength: 3 maxLength: 20 example: Primary Production VPN (Updated) pushed_routes: type: array description: >- An updated list of network routes (in CIDR notation) to be pushed to clients. items: type: string example: 10.0.0.0/8 public_dns: type: array description: An updated list of public DNS servers for clients. minItems: 2 maxItems: 4 items: type: string format: ipv4 example: 1.1.1.1 domains: type: array description: An updated list of domain names for split-tunnel DNS. maxItems: 8 items: type: string example: internal.corp split_dns: type: array description: An updated list of private DNS servers for split-tunnel DNS. items: type: string format: ipv4 example: 192.168.1.1 dns_custom: type: array description: An updated list of custom DNS records. items: type: object properties: name: type: string example: fileserver.internal.corp type: type: string enum: - A - CNAME example: A value: type: string example: 192.168.1.10 Instance: type: object properties: id: type: string format: uuid description: The unique identifier for the VPN instance. example: d290f1ee-6c54-4b01-90e6-d701748f0851 name: type: string description: A human-readable name for the instance. example: Primary Production VPN region: type: string description: The geographical region where the instance is deployed. example: sjc hostname: type: string description: The fully qualified domain name (FQDN) of the VPN instance. example: my-vpn-gateway.vpn.altostr.at configured: type: boolean description: Indicates if the initial server setup has completed. example: true rsa_ready: type: boolean description: Indicates if the RSA certificates have been generated. example: true diffie_hellman_ready: type: boolean description: Indicates if the Diffie-Hellman parameters have been generated. example: true server_ready: type: boolean description: A general indicator of the server's readiness. example: true status: type: array description: >- An array of strings indicating any ongoing configuration changes. An empty array means the configuration is stable. items: type: string example: - peer-created pushed_routes: type: array description: >- A list of network routes (in CIDR notation) that will be pushed to connecting clients. items: type: string example: 10.0.0.0/8 public_dns: type: array description: A list of public DNS servers to be used by clients. items: type: string format: ipv4 example: 9.9.9.9 split_dns: type: array description: >- A list of private DNS servers for specific domains (split-tunnel DNS). items: type: string format: ipv4 example: 192.168.1.1 domains: type: array description: >- A list of domain names that should be resolved using the split_dns servers. items: type: string example: internal.corp dns_custom: type: array description: >- A list of custom DNS records to be served by the instance's DNS proxy. items: type: object properties: name: type: string example: fileserver.internal.corp type: type: string enum: - A - CNAME example: A value: type: string example: 192.168.1.10 firewall: type: array description: A list of firewall rules applied to the instance. items: type: object properties: name: type: string example: Allow ICMP protocol: type: string enum: - tcp - udp - icmp - gre - esp - ah example: icmp port: type: string nullable: true example: 1-65535 source: type: string example: 0.0.0.0/0 destination: type: string example: 0.0.0.0/0 created_at: type: string format: date-time description: The timestamp when the instance was created. example: '2025-10-29T12:30:31Z' ErrorResponse: type: object properties: type: type: string description: A broad category for the error (e.g., 'invalid_request_error'). example: invalid_request_error code: type: string description: A short, unique string identifying the specific error. example: parameter_missing message: type: string description: A human-readable description of what went wrong. example: The 'name' parameter is required for this request. doc_url: type: string description: >- A direct link to the documentation page for this specific error code. example: https://docs.altostrat.io/errors/parameter_missing securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: JWT description: 'Enter your bearer token in the format: Bearer {token}' ````