diff --git a/src/server/utils/WireGuard.ts b/src/server/utils/WireGuard.ts
index 55e56b0e..bbf77ddf 100644
--- a/src/server/utils/WireGuard.ts
+++ b/src/server/utils/WireGuard.ts
@@ -6,8 +6,6 @@ import QRCode from 'qrcode';
 import CRC32 from 'crc-32';
 
 import type { NewClient } from '~~/services/database/repositories/client';
-import { parseCidr } from 'cidr-tools';
-import { stringifyIp } from 'ip-bigint';
 import { isIPv4 } from 'is-ip';
 
 const DEBUG = debug('WireGuard');
@@ -134,50 +132,9 @@ class WireGuard {
     const publicKey = await wg.getPublicKey(privateKey);
     const preSharedKey = await wg.generatePresharedKey();
 
-    // Calculate next IP
-    const cidr4 = parseCidr(system.userConfig.address4Range);
-    let address4;
-    for (let i = cidr4.start + 2n; i <= cidr4.end - 1n; i++) {
-      const currentIp4 = stringifyIp({ number: i, version: 4 });
-      const client = Object.values(clients).find((client) => {
-        return client.address4 === currentIp4;
-      });
-
-      if (!client) {
-        address4 = currentIp4;
-        break;
-      }
-    }
-
-    if (!address4) {
-      throw createError({
-        statusCode: 409,
-        statusMessage: 'Maximum number of clients reached.',
-        data: { cause: 'IPv4 Address Pool exhausted' },
-      });
-    }
+    const address4 = nextIPv4(system, clients);
 
-    const cidr6 = parseCidr(system.userConfig.address6Range);
-    let address6;
-    for (let i = cidr6.start + 2n; i <= cidr6.end - 1n; i++) {
-      const currentIp6 = stringifyIp({ number: i, version: 6 });
-      const client = Object.values(clients).find((client) => {
-        return client.address6 === currentIp6;
-      });
-
-      if (!client) {
-        address6 = currentIp6;
-        break;
-      }
-    }
-
-    if (!address6) {
-      throw createError({
-        statusCode: 409,
-        statusMessage: 'Maximum number of clients reached.',
-        data: { cause: 'IPv6 Address Pool exhausted' },
-      });
-    }
+    const address6 = nextIPv6(system, clients);
 
     // Create Client
     const id = crypto.randomUUID();
diff --git a/src/server/utils/config.ts b/src/server/utils/config.ts
index b26e60f0..87f8363d 100644
--- a/src/server/utils/config.ts
+++ b/src/server/utils/config.ts
@@ -2,6 +2,8 @@ import debug from 'debug';
 import packageJson from '@@/package.json';
 import { z } from 'zod';
 import type { Database } from '~~/services/database/repositories/database';
+import { parseCidr } from 'cidr-tools';
+import { stringifyIp } from 'ip-bigint';
 
 export const WG_PATH = process.env.WG_PATH || '/etc/wireguard/';
 
@@ -36,6 +38,7 @@ export async function migrateConfig(input: unknown) {
   }
   const system = await Database.getSystem();
   const oldConfig = res.data;
+  const oldCidr = parseCidr(oldConfig.server.address + '/24');
   const db = {
     system: {
       ...system,
@@ -47,12 +50,14 @@ export async function migrateConfig(input: unknown) {
       },
       userConfig: {
         ...system.userConfig,
-        address4Range: 'TODO',
+        address4Range:
+          stringifyIp({ number: oldCidr.start, version: 4 }) + '/24',
       },
     } satisfies Partial<Database['system']>,
     clients: {} as Database['clients'],
   };
   for (const [oldId, oldClient] of Object.entries(oldConfig.clients)) {
+    const address6 = nextIPv6(db.system, db.clients);
     db.clients[oldId] = {
       id: oldId,
       address4: oldClient.address,
@@ -66,10 +71,10 @@ export async function migrateConfig(input: unknown) {
       endpoint: null,
       expiresAt: null,
       oneTimeLink: null,
-      allowedIPs: ['0.0.0.0/0', '::/0'],
+      allowedIPs: db.system.userConfig.allowedIps,
       serverAllowedIPs: [],
       persistentKeepalive: 0,
-      address6: 'TODO',
+      address6: address6,
     };
   }
 }
diff --git a/src/server/utils/ip.ts b/src/server/utils/ip.ts
new file mode 100644
index 00000000..3f2fb5e3
--- /dev/null
+++ b/src/server/utils/ip.ts
@@ -0,0 +1,47 @@
+import { parseCidr } from 'cidr-tools';
+import { stringifyIp } from 'ip-bigint';
+import type { Database } from '~~/services/database/repositories/database';
+
+export function nextIPv4(
+  system: Database['system'],
+  clients: Database['clients']
+) {
+  return nextIP(4, system, clients);
+}
+
+export function nextIPv6(
+  system: Database['system'],
+  clients: Database['clients']
+) {
+  return nextIP(6, system, clients);
+}
+
+function nextIP(
+  version: 4 | 6,
+  system: Database['system'],
+  clients: Database['clients']
+) {
+  const cidr = parseCidr(system.userConfig[`address${version}Range`]);
+  let address;
+  for (let i = cidr.start + 2n; i <= cidr.end - 1n; i++) {
+    const currentIp = stringifyIp({ number: i, version: version });
+    const client = Object.values(clients).find((client) => {
+      return client[`address${version}`] === currentIp;
+    });
+
+    if (!client) {
+      address = currentIp;
+      break;
+    }
+  }
+
+  if (!address) {
+    throw createError({
+      statusCode: 409,
+      statusMessage: 'Maximum number of clients reached.',
+      data: { cause: `IPv${version} Address Pool exhausted` },
+    });
+  }
+
+  return address;
+}