# Configure number lists

The **Number List** feature in the DIDWW user panel allows you to manage inbound call filtering by specifying which
phone numbers or prefixes should be **allowed or rejected**. These lists can be linked to inbound **SIP** and **PSTN**
trunks, ensuring that only approved calls go through while unwanted ones are rejected.

This guide walks you through the process of creating a **Number List**, adding numbers or prefixes, and configuring
rules to either **allow or reject** calls. You'll learn how to:

- **Create a Number List** and assign it to an inbound **SIP** or **PSTN** trunk.
- **Define specific numbers or prefixes** to allow or reject calls.
- **Analyze call rejection error codes** to troubleshoot blocked calls and adjust settings.

To edit or delete existing Number Lists and their numbers, see [Manage number lists](manage-number-lists.html). For
example configurations, see [Number List use cases](../use-cases/index.html).

## Before you begin

- An active DIDWW account is required. [Sign in to DIDWW](https://my.didww.com/users/sign_in).
- An inbound SIP or PSTN trunk is required to assign the Number List to. See
  [Create a SIP trunk](../../sip-trunks/how-to-guides/create-sip-trunk.html)
  or [Create a PSTN trunk](../../pstn-trunks/how-to-guides/create-pstn-trunk.html).

## 1. Create a Number List

Before you can filter inbound calls, you need to create a **Number List**. This list will store numbers and prefixes
that can later be assigned to a **SIP** or **PSTN** trunk for call filtering.

Follow these steps to create a **Number List** to filter inbound calls.

### Step 1: Open the Create Inbound Number List

1. Go to **Voice > Inbound Trunks**.
2. Open the **Number Lists** tab.
3. Click **Create New** to start the setup.

[![Number Lists Create New Button](../../../../_images/fig1.1.png)](../../../../_images/fig1.1.png)


**Fig. 1.** Number Lists Create New Button

### Step 2: Configure the Number List

On the **Number List** creation screen, configure the list based on your requirements:

1. Enter a **Friendly name** (e.g., **Blocked Callers**).
2. Select a **Mode**:

   - **Full number match**: The number(s) must include the exact full source calling number to apply this rule.
   - **Prefix match**: The number(s) must include a prefix. This rule applies only if the source number matches your entered prefix(s).
3. Set the **Default action**:

   - **Allow call**: All calls will be allowed if no matching numbers are found in your number list.
   - **Reject call**: All calls will be rejected if no matching numbers are found in your number list.

[![Configure the Number List](../../../../_images/fig258.png)](../../../../_images/fig258.png)


**Fig. 2.** Configure the Number List

### Step 3: Create the Number List

Click **Create** to save your new **Number List**. It will now appear in the **Number Lists** section.

[![Create the Number List](../../../../_images/fig2.14.png)](../../../../_images/fig2.14.png)


**Fig. 3.** Create the Number List

## 2. Add and Configure Numbers in the Number List

After creating a **Number List**, the next step is to configure it by adding numbers or prefixes, setting actions to
**allow** or **reject** calls, and, if using prefixes, defining length limits.

Follow these steps to add numbers to an existing **Number List**.

### Step 1: Open the Number List

1. Go to **Voice > Inbound Trunks**.
2. Open the **Number Lists** tab.
3. Choose the list where you would like to add or manage numbers and click the **Actions** button.
4. Select **Manage numbers** or click **Add numbers**.

[![Open Manage or Add Numbers.](../../../../_images/step1_open_the_add_numbers.png)](../../../../_images/step1_open_the_add_numbers.png)


**Fig. 4.** Open Manage or Add Numbers.

### Step 2: Add Numbers to the Number List

On the **Manage Numbers** page, you can view and modify the list of previously added numbers. You can add new numbers,
remove existing ones, or adjust their settings to **allow** or **reject** calls based on your needs.

1. Click **Add Numbers** from the **Manage Numbers** page or within the **Number List** page to open the number entry dialog.

[![Add Number Button.](../../../../_images/fig438.png)](../../../../_images/fig438.png)


**Fig. 5.** Add Number Button.

2. When the **Add Numbers** pop-up appears, enter the **Numbers or prefixes to be added** to the list.

   - Separate multiple numbers with a comma or a new line (e.g., `15551234567, 1234567890`).

[![Comma Separated Numbers](../../../../_images/fig4.17.png)](../../../../_images/fig4.17.png)


**Fig. 6.** Comma Separated Numbers

### Step 3: Configure Number Actions & Save Changes

A mandatory action must be selected to either **allow** or **reject** calls for the added numbers or prefixes.

1. Select an **Action**:

   - **Allow call**: The call will be allowed if the source number matches a number or prefix in your list. This action overrides any rules set in your number list.
   - **Reject call**: The call will be rejected if the source number matches a number or prefix in your list. This action overrides any rules set in your number list.
2. **(Optional)** When using prefixes for routing, adjust the **Min. Length** and **Max. Length** fields. These settings define the range of phone numbers the rule applies to:

   - **Min. Length**: The shortest phone number that can match the prefix (**default: 0**).
   - **Max. Length**: The longest phone number that can match the prefix (**default: 100**).
3. Click **Submit** to save the changes.

[![Number List Settings](../../../../_images/configure_number_actions.png)](../../../../_images/configure_number_actions.png)


**Fig. 7.** Number List Settings

## 3. Assign a Number List to a Trunk

After creating and configuring your **Number List**, you can assign it to a trunk to apply inbound call filtering rules.

Number Lists can be assigned to either a **SIP Trunk** or a **PSTN Trunk**, depending on your routing setup.

### Assign a Number List to a SIP Trunk

Follow these steps to assign a Number List to a **SIP Trunk**.

#### Step 1: Open the SIP Trunk

1. Go to **Voice > Inbound Trunks**.
2. Choose an existing **SIP Trunk** by clicking its name, and then click **Actions > Edit** on the trunk page. You can also create a new one (see [Create a SIP trunk](../../sip-trunks/how-to-guides/create-sip-trunk.html)).

[![Selecting an inbound SIP trunk](../../../../_images/voice_trunks.png)](../../../../_images/voice_trunks.png)


**Fig. 8.** Selecting an inbound SIP trunk

#### Step 2: Assign the Number List

1. Open the **Number Translations** tab, locate **CLI Number List**, and select the Number List you want to assign.
2. Click **Submit** to save the changes.

Warning

Number Lists match inbound caller ID (CLI). If you change the **CLI format** or **CLI prefix** in the [SIP
trunk](../../sip-trunks/sip-trunk-settings-reference.html) settings, update your **Number List** entries to match the
new format. CLI format conversion may not work correctly for calls originating from outside the country of the DID.

[![Assigning a Number List to a SIP Trunk](../../../../_images/sip_trunk.png)](../../../../_images/sip_trunk.png)


**Fig. 9.** Assigning a Number List to a SIP Trunk

### Assign a Number List to a PSTN Trunk

Follow these steps to assign a Number List to a **PSTN Trunk**.

#### Step 1: Open the PSTN Trunk

1. Go to **Voice > Inbound Trunks**.
2. Choose an existing **PSTN Trunk** by clicking its name, and then click **Actions > Edit** on the trunk page. You can also create a new one (see [Create a PSTN trunk](../../pstn-trunks/how-to-guides/create-pstn-trunk.html)).

[![Selecting an inbound PSTN trunk](../../../../_images/pstn1.png)](../../../../_images/pstn1.png)


**Fig. 10.** Selecting an inbound PSTN trunk

#### Step 2: Assign the Number List

1. Open the **Number Translations** tab, locate **CLI Number List**, and select the Number List you want to assign.
2. Click **Submit** to save the changes.

[![Assigning a Number List to a PSTN Trunk](../../../../_images/pstn2.png)](../../../../_images/pstn2.png)


**Fig. 11.** Assigning a Number List to a PSTN Trunk

## Call Logs & Number List Rejection Codes

When a call is rejected due to **Number List filtering**, it will appear in the **Inbound Call Logs** with the following
error message:

- **Error code:** 403
- **Response:** Rejected by trunk settings

This error message in the call logs indicates that the call was blocked by **Number List** settings before it could
reach the trunk destination.

### Why does this error occur?

If a number is included in a **Number List** with the action **Reject call**, the system blocks the call **before
routing it to the trunk destination**. The same happens when no item matches the number and the **Number List** has the
**Default action** **Reject call**.

This prevents further call processing, leading to the **403** error.

### How can I check inbound call rejections caused by a Number List?

Follow these steps to analyze calls rejected due to a **Number List**:

1. Navigate to **Logs & Analytics > Call Logs** and select the **Inbound** tab.
2. Look for calls that failed with the **Rejected by trunk settings** response. (You can also filter by status: **Failed**.)
3. Check if the caller's number is listed in your **Number List**.

Note

If you want to **allow** a blocked number, go to your **Number List** settings and change its action to **Allow call**
or remove it from the list.

[![Call Rejection Error Code](../../../../_images/call_logs.png)](../../../../_images/call_logs.png)


**Fig. 12.** Call Rejection Error Code

## Related resources

- [Manage number lists](manage-number-lists.html) - Edit or delete Number
  Lists and the numbers in them.
- [Number List use cases](../use-cases/index.html) - Learn how to configure
  Number Lists with real-world scenarios.
- [Number List settings reference](../number-list-settings-reference.html) -
  Look up field definitions, defaults, values, and limits.
- [Inbound Call Logs](../../../../logs-analytics/call-logs/inbound-logs.html#inbound-cdr-logs) - Review and analyze your inbound
  call logs.

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