diff --git a/epp/src/helpers.php b/epp/src/helpers.php
index 20da880..8e748d3 100644
--- a/epp/src/helpers.php
+++ b/epp/src/helpers.php
@@ -615,4 +615,31 @@ function generateAuthInfo(): string {
     }
 
     return $retVal;
+}
+
+function isIPv6($ip) {
+    // Validate if the IP is in IPv6 format
+    return filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) !== false;
+}
+
+function expandIPv6($ip) {
+    if (strpos($ip, '::') !== false) {
+        // Split the IP by '::'
+        $parts = explode('::', $ip);
+        $left = explode(':', $parts[0]);
+        $right = isset($parts[1]) ? explode(':', $parts[1]) : [];
+
+        // Calculate the number of missing groups and fill them with '0000'
+        $fill = array_fill(0, 8 - (count($left) + count($right)), '0000');
+        $expanded = array_merge($left, $fill, $right);
+    } else {
+        $expanded = explode(':', $ip);
+    }
+
+    // Ensure each block is four characters
+    foreach ($expanded as &$block) {
+        $block = str_pad($block, 4, '0', STR_PAD_LEFT);
+    }
+
+    return implode(':', $expanded);
 }
\ No newline at end of file
diff --git a/epp/start_epp.php b/epp/start_epp.php
index 85bd13e..321c857 100644
--- a/epp/start_epp.php
+++ b/epp/start_epp.php
@@ -76,6 +76,9 @@ $server->handle(function (Connection $conn) use ($table, $pool, $c, $log, $permi
     // Get the client information
     $clientInfo = $conn->exportSocket()->getpeername();
     $clientIP = isset($clientInfo['address']) ? (strpos($clientInfo['address'], '::ffff:') === 0 ? substr($clientInfo['address'], 7) : $clientInfo['address']) : '';
+    if (isIPv6($clientIP)) {
+        $clientIP = expandIPv6($clientIP);
+    }
 
     // Check if the IP is in the permitted list
     if (!$permittedIPsTable->exist($clientIP)) {