---
title: "ACG"
slug: "server-acg-classic"
tags: ["Classic", "Server", "ACG"]
updated: 2026-09-17T09:17:40Z
published: 2026-09-17T09:17:40Z
canonical: "guide.ncloud-docs.com/server-acg-classic"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://guide.ncloud-docs.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ACG

Available in Classic

ACG describes the screen configuration of the **ACG** menu and ACG information and explains how to create, set, and delete an ACG.

Access Control Group (ACG) is an IP/Port-based filtering firewall service that enables you to control and manage network access between servers. By using ACG, you can easily establish and manage ACG rules for server groups without needing to separately manage the existing firewalls (iptables, UFW, and Windows firewall). You can use the ACG provided by default in NAVER Cloud Platform, or set rules for the ACG you create to use it.

              Note

              

- The following are the restrictions in using ACG.
  - You can create up to 100 ACGs per account.
  - Up to 100 rules can be set for each ACG.
  - A server can be repeatedly included in up to 5 ACGs.
  - The ACG selected at server creation can't be changed, and the ACG rules apply until termination of the server.
- When you create a load balancer, an ACG (ncloud-load-balancer) for the load balancer is created automatically. To use the service, the permission rule that specifies the access source as the load balancer must be added in the ACG of the server actually bound by the load balancer.
- After the permission rule for the load balancer is added to the ACG, communications with servers can continue if there is continued health check request by the load balancer for servers, even if the rule is deleted later. To block the communication with the server, restart the connected load balancer.

## Check ACG information

You can check ACG information on the ACG page.

### ACG page

From the NAVER Cloud Platform portal, click the **Console** > **Menu** > **All Services** > **Compute> Server** > **ACG** menus, in that order, to view the ACG page.

The ACG page is laid out as follows:

![server-acg-classic_screen_ko](https://cdn.document360.io/6998976f-9d95-4df8-b847-d375892b92c2/Images/Documentation/server-acg-classic_screen_en.png?sv=2026-02-06&spr=https&st=2026-11-14T05%3A05%3A09Z&se=2026-11-14T06%3A05%3A09Z&sr=c&sp=r&sig=yyX5OBlVTyMafLAzjqT%2B5lyXEn7aO2UMNCseYD9FIHU%3D)

| Field | Description |
| --- | --- |
| ① Menu name | Name of the menu currently being checked and the number of created ACGs |
| ② Basic features | Features provided on the first page when the user enters the **ACG** menu - **[Create ACG]** button: click to [create ACG](/docs/en/server-acg-classic#ACG%EC%83%9D%EC%84%B1) - **[Learn more about products]** button: click to move to the Server introduction page - **[Download]** button: click to download the ACG list as an Excel file - **[Refresh]** button: click to refresh the ACG list |
| ③ Post-creation features | Features provided after creating the ACG - **[Set ACG]** button: click to [set the selected ACG](/docs/en/server-acg-classic#ACG%EC%84%A4%EC%A0%95) - **[Delete ACG]** button: click to [delete the selected ACG](/docs/en/server-acg-classic#ACG%EC%82%AD%EC%A0%9C) |
| ④ ACG list | List of created ACGs - **ACG name**: name entered when creating the ACG - **ACG ID**: ID automatically given when creating the ACG - **Number of applied servers**: number of servers with the ACG applied - **Number of rules applied**: number of the rules configured for the ACG - **Creation date and time**: date and time when the ACG was created - **Target server**: information about the servers applied with the ACG - **View rules**: displays information of rules configured for the ACG |

## Create ACG

The Default ACG (ncloud-default-acg) is provided without creating an ACG in NAVER Cloud Platform, but you can create and use a separate ACG. For more information about Default ACG, see [ACG specifications](/docs/en/server-spec-classic#ACG%EC%82%AC%EC%96%91).

The following describes how to create an ACG.

1. In the Classic environment of the NAVER Cloud Platform console, navigate to **Menu** > **All Services** > **Compute** > **Server**.
2. Click the **ACG** menu.
3. Click the **[Create ACG]** button.
4. Enter the name of ACG, and click the **[Create]** button.
  - An ACG is created and displayed in the ACG list.
  - ACGs directly created by users have no rules provided by default. Set the rules through [Set ACG](/docs/en/server-acg-classic#ACG%EC%84%A4%EC%A0%95).

## Set ACG

The following describes how to set detailed rules for the Default ACG and the ACGs you created.

1. In the Classic environment of the NAVER Cloud Platform console, navigate to **Menu** > **All Services** > **Compute** > **Server**.
2. Click the **ACG** menu.
3. Click to select the ACG to set rules for from the ACG list, and then click the **[Set ACG]** button.
4. Enter the detailed rules by referring to the following table, and then click the **[Add]** button.

| Item | Setup method | Examples |
| --- | --- | --- |
| **Protocol** | Select from TCP, UDP, and ICMP | - |
| **Access source** | Enter the IP address or ACG name - IP address - ACG name | - Example of entering CIDR: 0.0.0.0/0, 192.168.1.0/24 - Example of entering ACG name: my-acg-1 (preset name of ACG) |
| **Allowed port (service)** | Enter the allowed port range for selecting TCP and UDP | - 22 (for ssh service) - 3389 (for remote Windows access) |
| **Notes** | Enter briefly, if necessary | - |
5. After adding all the rules, click the **[Apply]** button.
  - The set rules are applied to ACG.

### ACG rule settings example

The frequently used ACG rules are as follows:

- Allows access to SSH service from a specific IP address

| Protocol | Access source | Allowed port |
| --- | --- | --- |
| TCP | 192.168.77.17 | 22 |
- Allows access to SSH service from a specific IP address range (1)

| Protocol | Access source | Allowed port |
| --- | --- | --- |
| TCP | 192.168.77.0/24 | 22 |
- Allows access to SSH service from a specific IP address range (2)

| Protocol | Access source | Allowed port |
| --- | --- | --- |
| TCP | 192.168.77.128/25 | 22 |
- Allows SSH access between servers assigned to ACG named Test-ACG

| Protocol | Access source | Allowed port |
| --- | --- | --- |
| TCP | Test-ACG | 22 |
- Sets the ncloud-load-balancer, an ACG for the load balancer, as an access source to allow network access to the web server that the load balancer binds

| Protocol | Access source | Allowed port |
| --- | --- | --- |
| TCP | ncloud-load-balancer | 80 |
  - Even if several load balancers are created, the name of the ACG must be the same.
- Allows access to UDP 22-1025 port from specific IPs

| Protocol | Access source | Allowed port |
| --- | --- | --- |
| UDP | 192.168.77.17 | 22-1025 |
- Allows access to the entire web service

| Protocol | Access source | Allowed port |
| --- | --- | --- |
| TCP | 0.0.0.0/0 | 80 |

## Delete ACG

The following describes how to delete an ACG.

              Note

              

- You cannot delete several ACGs at the same time.
- You can't delete ACGs applied to servers.

1. In the Classic environment of the NAVER Cloud Platform console, navigate to **Menu** > **All Services** > **Compute** > **Server**.
2. Click the **ACG** menu.
3. Click to select the ACG to delete from the ACG list, and then click the **[Delete ACG]** button.
4. Check the pop-up message and click the **[OK]** button.
  - The ACG is deleted and disappears from the list.