diff --git a/public/i18n/en/translation.json b/public/i18n/en/translation.json
index 77626e56..60af4722 100644
--- a/public/i18n/en/translation.json
+++ b/public/i18n/en/translation.json
@@ -907,7 +907,8 @@
       "create_bond": "Create bond",
       "configure_bond": "Configure bond",
       "configure_bond_name": "Configure bond {name}",
-      "clients_network": "Clients network"
+      "clients_network": "Clients network",
+      "pppoe_name_too_long_need_reconfiguration": "PPPoE interface names are limited to {num} characters. You can remove the configuration from this device, then reconfigure it with a shorter interface name."
     },
     "multi_wan": {
       "title": "MultiWAN",
diff --git a/src/components/standalone/interfaces_and_devices/ConfigureDeviceDrawer.vue b/src/components/standalone/interfaces_and_devices/ConfigureDeviceDrawer.vue
index 01f1afbf..2ac4a10e 100644
--- a/src/components/standalone/interfaces_and_devices/ConfigureDeviceDrawer.vue
+++ b/src/components/standalone/interfaces_and_devices/ConfigureDeviceDrawer.vue
@@ -657,6 +657,9 @@ function validate() {
         if (logicalIfaceType.value == 'bond') {
           maxLen = 10
         }
+        if (protocol.value == 'pppoe') {
+          maxLen = 5
+        }
         let { valid, errMessage, i18Params } = validateUciName(interfaceName.value, maxLen)
         if (!valid) {
           error.value.interfaceName = t(errMessage as string, i18Params as any)
@@ -665,6 +668,20 @@ function validate() {
             focusElement(interfaceNameRef)
           }
         }
+      } else {
+        // editing an already configured device
+        if (protocol.value == 'pppoe' && interfaceName.value.length > 5) {
+          error.value.interfaceName = t(
+            'standalone.interfaces_and_devices.pppoe_name_too_long_need_reconfiguration',
+            {
+              num: 5
+            }
+          )
+          if (isValidationOk) {
+            isValidationOk = false
+            focusElement(interfaceNameRef)
+          }
+        }
       }
 
       if (isConfiguringFromScratch.value) {