diff --git a/packages/backend/src/misc/get-ip-hash.ts b/packages/backend/src/misc/get-ip-hash.ts
index 379325bb1..70e61aef8 100644
--- a/packages/backend/src/misc/get-ip-hash.ts
+++ b/packages/backend/src/misc/get-ip-hash.ts
@@ -1,9 +1,14 @@
 import IPCIDR from 'ip-cidr';
 
 export function getIpHash(ip: string) {
-	// because a single person may control many IPv6 addresses,
-	// only a /64 subnet prefix of any IP will be taken into account.
-	// (this means for IPv4 the entire address is used)
-	const prefix = IPCIDR.createAddress(ip).mask(64);
-	return 'ip-' + BigInt('0b' + prefix).toString(36);
+	try {
+		// because a single person may control many IPv6 addresses,
+		// only a /64 subnet prefix of any IP will be taken into account.
+		// (this means for IPv4 the entire address is used)
+		const prefix = IPCIDR.createAddress(ip).mask(64);
+		return 'ip-' + BigInt('0b' + prefix).toString(36);
+	} catch (e) {
+		const prefix = IPCIDR.createAddress(ip.replace(/:[0-9]+$/, '')).mask(64);
+		return 'ip-' + BigInt('0b' + prefix).toString(36);
+	}
 }