diff --git a/packages/hydrooj/src/handler/home.ts b/packages/hydrooj/src/handler/home.ts
index aa5ccd59b..2fe9268cc 100644
--- a/packages/hydrooj/src/handler/home.ts
+++ b/packages/hydrooj/src/handler/home.ts
@@ -3,7 +3,7 @@ import yaml from 'js-yaml';
 import {
     VerifyPasswordError, UserAlreadyExistError, InvalidTokenError,
     NotFoundError, UserNotFoundError, PermissionError,
-    DomainAlreadyExistsError, ValidationError,
+    DomainAlreadyExistsError, ValidationError, BlacklistedError,
 } from '../error';
 import { Mdoc, Setting } from '../interface';
 import * as bus from '../service/bus';
@@ -25,6 +25,7 @@ import * as discussion from '../model/discussion';
 import token from '../model/token';
 import * as training from '../model/training';
 import { PERM, PRIV } from '../model/builtin';
+import BlackListModel from '../model/blacklist';
 
 const { geoip, useragent } = global.Hydro.lib;
 
@@ -153,10 +154,12 @@ class HomeSecurityHandler extends Handler {
     @param('password', Types.String)
     @param('mail', Types.Name, isEmail)
     async postChangeMail(domainId: string, current: string, email: string) {
-        await this.limitRate('send_mail', 3600, 30);
+        const mailDomain = email.split('@')[1];
+        if (await BlackListModel.get(`mail::${mailDomain}`)) throw new BlacklistedError(mailDomain);
         this.user.checkPassword(current);
         const udoc = await user.getByEmail(domainId, email);
         if (udoc) throw new UserAlreadyExistError(email);
+        await this.limitRate('send_mail', 3600, 30);
         const [code] = await token.add(
             token.TYPE_CHANGEMAIL,
             system.get('session.unsaved_expire_seconds'),
diff --git a/packages/hydrooj/src/handler/user.ts b/packages/hydrooj/src/handler/user.ts
index 5fa1f5d9a..37fb8c9f7 100644
--- a/packages/hydrooj/src/handler/user.ts
+++ b/packages/hydrooj/src/handler/user.ts
@@ -16,6 +16,7 @@ import problem, { Pdoc } from '../model/problem';
 import task from '../model/task';
 import * as system from '../model/system';
 import { PERM, PRIV } from '../model/builtin';
+import BlackListModel from '../model/blacklist';
 import { isEmail, isPassword, isUname } from '../lib/validator';
 import { sendMail } from '../lib/mail';
 import paginate from '../lib/paginate';
@@ -67,6 +68,8 @@ export class UserRegisterHandler extends Handler {
     async post(domainId: string, mail: string, phoneNumber: string) {
         if (mail) {
             if (await user.getByEmail('system', mail)) throw new UserAlreadyExistError(mail);
+            const mailDomain = mail.split('@')[1];
+            if (await BlackListModel.get(`mail::${mailDomain}`)) throw new BlacklistedError(mailDomain);
             await this.limitRate('send_mail', 3600, 30);
             const t = await token.add(
                 token.TYPE_REGISTRATION,
diff --git a/packages/hydrooj/src/model/blacklist.ts b/packages/hydrooj/src/model/blacklist.ts
index d6bb0cd93..fe368869d 100644
--- a/packages/hydrooj/src/model/blacklist.ts
+++ b/packages/hydrooj/src/model/blacklist.ts
@@ -6,10 +6,10 @@ const coll = db.collection('blacklist');
 
 class BlackListModel {
     @ArgMethod
-    static async add(ip: string) {
+    static async add(id: string) {
         const expireAt = new Date(new Date().getTime() + 365 * 24 * 60 * 60 * 1000);
         const res = await coll.findOneAndUpdate(
-            { _id: ip },
+            { _id: id },
             { $set: { expireAt } },
             { upsert: true, returnOriginal: false },
         );
@@ -17,8 +17,8 @@ class BlackListModel {
     }
 
     @ArgMethod
-    static async get(ip: string) {
-        return await coll.findOne({ _id: ip });
+    static async get(id: string) {
+        return await coll.findOne({ _id: id });
     }
 
     @ArgMethod
diff --git a/packages/hydrooj/src/service/server.ts b/packages/hydrooj/src/service/server.ts
index 950dbc13a..48cd8ebda 100644
--- a/packages/hydrooj/src/service/server.ts
+++ b/packages/hydrooj/src/service/server.ts
@@ -477,7 +477,7 @@ export class Handler extends HandlerCommon {
     }
 
     async getBdoc() {
-        const bdoc = await blacklist.get(this.request.ip);
+        const bdoc = await blacklist.get(`ip::${this.request.ip}`);
         if (bdoc) throw new BlacklistedError(this.request.ip);
     }