# Create an SMPP ESME trunk Create an SMPP ESME trunk so that your application can bind to the DIDWW SMSC to send and receive SMS. Set the trunk name and **Server location**, choose which IP addresses can connect, limit the DID numbers that can be used as the sender ID, and optionally add the trunk to an SMS trunk group. For how your application connects to DIDWW and exchanges messages, see [SMPP ESME trunk](../smpp-esme-trunk.html). ## Before you begin - An active DIDWW account is required. [Sign in to DIDWW](https://my.didww.com/users/sign_in) or [Create DIDWW account](https://my.didww.com/users/sign_up#/users/sign_up). - To use your DID numbers as sender IDs, at least one DID number with outbound P2P SMS enabled is required. See [P2P Outbound SMS access](../../../how-sms-service-works.html#how-sms-service-works-p2p-access). ## Step 1: Open the creation form 1. In the DIDWW User Panel, go to **SMS > SMS Trunks**. 2. Click **Create New** in the top-right corner. 3. Select **SMPP ESME**. [![Create New menu on the SMS Trunks page with SMPP ESME highlighted](../../../../_images/fig165.png)](../../../../_images/fig165.png) **Fig. 1.** Select SMPP ESME ## Step 2: Configure the General settings In the **General** section, name the trunk, choose the DIDWW SMPP server that your application binds to, and choose which IP addresses can connect. 1. In **Friendly name**, enter a unique, descriptive name to identify the trunk. 2. Optionally, in **System type**, enter a value that categorizes your ESME, for example `VMS` (voice mail system) or `OTA` (over-the-air activation system). Your application sends this value as the `system_type` bind parameter. 3. In **Server location**, select **US, NY** or **NL, AMS**. The location determines the **Host** that your application binds to. 4. Optionally, in **Allowed IP addresses**, enter each IP address from which your application connects, in the format `(IPv4|IPv6)[/mask]`, and press **Enter**. If an entry is marked as invalid, correct it or click **Remove invalid**. If the field is empty, connections from all IP addresses are allowed. Field definitions, formats, and constraints are listed in [General settings](../smpp-esme-trunk-settings-reference.html#smpp-esme-settings-general). Important Your application connects to the DIDWW SMPP server of the trunk's **Server location**. Your firewall must allow your application to open connections to that server's IP address. See [Server locations and IP addresses](../../technical-data/smpp-specification.html#smpp-endpoints). [![Create SMPP ESME Trunk form with Friendly name, System type, Server location, and Allowed IP addresses in the General section](../../../../_images/fig22.webp)](../../../../_images/fig22.webp) **Fig. 2.** Configure the General settings ## Step 3: Configure the source addresses By default, **Allow any DID(s) for SMS OUT** is on, and all DIDs with Outbound P2P SMS enabled in your account can be used as the sender ID. To allow only specific DID numbers, restrict the source addresses. Otherwise, skip this step. 1. In **Source Address Settings**, turn off **Allow any DID(s) for SMS OUT**. 2. In **Available source addresses**, select the DID numbers to allow. To find numbers, filter the list by **Source address**, **Description**, **Country**, or **Region**. 3. Click the right arrow button to add the selected numbers to **Allowed source addresses**, or click **Add all** to add every listed number. Only the numbers you add are available as sender IDs. To remove numbers, select them in **Allowed source addresses** and click the left arrow button, or click **Remove all**. Field definitions are listed in [Source address settings](../smpp-esme-trunk-settings-reference.html#smpp-esme-settings-source-address). Note When the **Allow any DID(s) for SMS OUT** toggle is turned off, the **Available source addresses** list shows only DIDs that support outbound P2P SMS. [![Allow any DID(s) for SMS OUT turned off and a DID number moved from Available source addresses to Allowed source addresses](../../../../_images/gif19.gif)](../../../../_images/gif19.gif) **Fig. 3.** Select the allowed source addresses ## Step 4: Add the trunk to a trunk group (optional) You may assign the trunk to an existing SMS trunk group in order to enable failover for inbound SMS. Within the trunk group, the trunk's priority determines the order in which trunks will be used. If the trunk will not be part of a trunk group, skip to Step 5. 1. Expand the **Trunk Group Configuration** section and select the group in **Assign to trunk group**. 2. In **Priority**, enter the trunk's priority within the group, from `0` to `32767`. Field definitions are listed in [Trunk group settings](../smpp-esme-trunk-settings-reference.html#smpp-esme-settings-trunk-group). To create a group, see [Create an SMS trunk group](../../trunk-groups/how-to-guides/create-sms-trunk-group.html). Note The system attempts to contact the target SMS trunk with the highest-numbered priority first. [![Trunk Group Configuration section of the Create SMPP ESME Trunk form with the Assign to trunk group and Priority fields](../../../../_images/trunk_group1.webp)](../../../../_images/trunk_group1.webp) **Fig. 4.** Configure the trunk group settings ## Step 5: Create the trunk Click **Create** at the bottom of the page to save the new trunk. The new trunk appears on the **SMS Trunks** page. DIDWW generates its **System ID** and **Password**, which your application uses to bind. Creating the trunk does not assign it to a DID number. [![Create button highlighted on the Create SMPP ESME Trunk form](../../../../_images/create2.webp)](../../../../_images/create2.webp) **Fig. 5.** Create the trunk ## Next steps - [View the trunk credentials](view-smpp-esme-trunk-credentials.html) to get the **Host**, **Port**, **System ID**, and **Password** for your application. - [Bind your application](bind-smpp-esme-trunk.html) to the DIDWW SMSC with the trunk credentials. - To receive SMS, [assign the trunk](../../../../phone-numbers/my-numbers/how-to-guides/assign-sms-trunk.html#assigning-sms-trunk) to one or more DIDs that support inbound SMS. For outbound SMS, DID assignment is not required. - To send A2P messages with a verified Sender ID, associate an active [Sender ID Verification](../../../sender-id-verifications/index.html) with the trunk. ## Related resources - [SMPP ESME trunk settings reference](../smpp-esme-trunk-settings-reference.html) - Look up field definitions, defaults, and constraints. - [SMPP ESME trunk](../smpp-esme-trunk.html) - Understand how your application connects to DIDWW and exchanges messages. - [Assign an SMS trunk](../../../../phone-numbers/my-numbers/how-to-guides/assign-sms-trunk.html#assigning-sms-trunk) - Assign the trunk to one or more DID numbers to start receiving messages. - [Send and receive SMS with OpenSIPS](../../../../integrations/opensips/sms.html#opensips-sms-integration) - Connect OpenSIPS 4.0 to an SMPP ESME trunk to send SMS, receive SMS, and receive delivery receipts. - [Manage SMPP ESME trunks](manage-smpp-esme-trunk.html) - Edit or delete an existing SMPP ESME trunk. - [Sender ID Verifications](../../../sender-id-verifications/index.html) - Verify Sender IDs for A2P messaging through the trunk.