diff --git a/lib/private/Net/IpAddressClassifier.php b/lib/private/Net/IpAddressClassifier.php
index b73d41fd79b..9d701b21e41 100644
--- a/lib/private/Net/IpAddressClassifier.php
+++ b/lib/private/Net/IpAddressClassifier.php
@@ -9,6 +9,7 @@ declare(strict_types=1);
 
 namespace OC\Net;
 
+use IPLib\Address\IPv4;
 use IPLib\Address\IPv6;
 use IPLib\Factory;
 use IPLib\ParseStringFlag;
@@ -42,7 +43,15 @@ class IpAddressClassifier {
 		}
 		/* Replace by normalized form */
 		if ($parsedIp instanceof IPv6) {
-			$ip = (string)($parsedIp->toIPv4() ?? $parsedIp);
+			$ipv4 = $parsedIp->toIPv4();
+			$ipv6Bytes = $parsedIp->getBytes();
+			if ($ipv4) {
+				$ip = (string)$ipv4;
+			} elseif (array_slice($ipv6Bytes, 0, 4) === [0x00, 0x64, 0xFF, 0x9B]) {
+				$ip = (string)IPv4::fromBytes(array_slice($ipv6Bytes, -4, 4));
+			} else {
+				$ip = (string)$parsedIp;
+			}
 		} else {
 			$ip = (string)$parsedIp;
 		}
diff --git a/tests/lib/Net/IpAddressClassifierTest.php b/tests/lib/Net/IpAddressClassifierTest.php
index 755b9171c79..d4d8bf5cd22 100644
--- a/tests/lib/Net/IpAddressClassifierTest.php
+++ b/tests/lib/Net/IpAddressClassifierTest.php
@@ -52,6 +52,7 @@ class IpAddressClassifierTest extends TestCase {
 			['::1'],
 			['100.100.100.200'],
 			['192.0.0.1'],
+			['64:ff9b::a9fe:a9fe'], // NAT64 of 169.254.169.254
 		];
 	}