diff --git a/backend/chatServer/src/chat/chat.gateway.ts b/backend/chatServer/src/chat/chat.gateway.ts
index 6c4b52a2..93211dfd 100644
--- a/backend/chatServer/src/chat/chat.gateway.ts
+++ b/backend/chatServer/src/chat/chat.gateway.ts
@@ -178,10 +178,10 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
 
     if(!address) throw new ChatException(CHATTING_SOCKET_ERROR.INVALID_USER, roomId);
 
-    const forwarded = banUser?.handshake.headers.forwarded ?? address;
-    console.log('ban:', roomId, address, forwarded);
+    const userAgent = banUser?.handshake.headers['user-agent'];
+    if(!userAgent) throw new ChatException(CHATTING_SOCKET_ERROR.INVALID_USER, roomId);
 
-    await this.roomService.addUserToBlacklist(roomId, address, forwarded);
+    await this.roomService.addUserToBlacklist(roomId, address, userAgent);
     console.log(await this.roomService.getUserBlacklist(roomId, address));
   }
 }
diff --git a/backend/chatServer/src/chat/chat.guard.ts b/backend/chatServer/src/chat/chat.guard.ts
index 3246cfaf..0a66e366 100644
--- a/backend/chatServer/src/chat/chat.guard.ts
+++ b/backend/chatServer/src/chat/chat.guard.ts
@@ -37,19 +37,20 @@ export class BlacklistGuard implements CanActivate {
 
     const client: Socket = context.switchToWs().getClient<Socket>();
     const address = client.handshake.address.replaceAll('::ffff:', '');
-    const forwarded = client.handshake.headers.forwarded?.split(',')[0] ?? address;
+    const userAgent = client.handshake.headers['user-agent'];
 
-    const isValidUser = await this.whenJoinRoom(roomId, address, forwarded);
+    if(!userAgent) throw new ChatException(CHATTING_SOCKET_ERROR.INVALID_USER, roomId);
+    const isValidUser = await this.whenJoinRoom(roomId, address, userAgent);
 
     if(!isValidUser) throw new ChatException(CHATTING_SOCKET_ERROR.BAN_USER, roomId);
     return true;
   }
 
-  async whenJoinRoom(roomId: string, address: string, forwarded: string) {
-    console.log(roomId, address, forwarded);
+  async whenJoinRoom(roomId: string, address: string, userAgent: string) {
+    console.log(roomId, address, userAgent);
     const blacklistInRoom = await this.roomService.getUserBlacklist(roomId, address);
     console.log(blacklistInRoom);
-    const isInBlacklistUser = blacklistInRoom.some((blackForwarded) => blackForwarded === forwarded);
+    const isInBlacklistUser = blacklistInRoom.some((bannedUserAgent) => bannedUserAgent === userAgent);
     console.log('blacklistInRoom:', isInBlacklistUser);
     return !isInBlacklistUser;
   }
diff --git a/backend/chatServer/src/room/room.repository.ts b/backend/chatServer/src/room/room.repository.ts
index 18fc4d51..16cf757a 100644
--- a/backend/chatServer/src/room/room.repository.ts
+++ b/backend/chatServer/src/room/room.repository.ts
@@ -3,7 +3,7 @@ import { Cluster } from 'ioredis';
 import { QuestionDto } from '../event/dto/Question.dto';
 import { ChatException, CHATTING_SOCKET_ERROR } from '../chat/chat.error';
 
-type FORWARDED = string;
+type USER_AGENT = string;
 
 @Injectable()
 export class RoomRepository {
@@ -128,16 +128,16 @@ export class RoomRepository {
   }
 
 
-  async getUserBlacklist(roomId: string, address: string): Promise<FORWARDED[]> {
-    const userBlacklist = await this.lrange<FORWARDED[]>(this.getUserBlacklistInRoomWithPrefix(roomId, address), 0, -1);
+  async getUserBlacklist(roomId: string, address: string): Promise<USER_AGENT[]> {
+    const userBlacklist = await this.lrange<USER_AGENT[]>(this.getUserBlacklistInRoomWithPrefix(roomId, address), 0, -1);
     console.log('blacklist', userBlacklist);
     if (!userBlacklist) return [];
     return userBlacklist;
   }
 
-  async addUserBlacklistToRoom(roomId: string, address: string, forwarded: string){
-    console.log(roomId, address, forwarded);
+  async addUserBlacklistToRoom(roomId: string, address: string, userAgent: string){
+    console.log(roomId, address, userAgent);
     console.log(this.getUserBlacklistInRoomWithPrefix(roomId, address));
-    return this.redisClient.rpush(this.getUserBlacklistInRoomWithPrefix(roomId, address), forwarded);
+    return this.redisClient.rpush(this.getUserBlacklistInRoomWithPrefix(roomId, address), userAgent);
   }
 }
diff --git a/backend/chatServer/src/room/room.service.ts b/backend/chatServer/src/room/room.service.ts
index f2e16a89..cfa9caf6 100644
--- a/backend/chatServer/src/room/room.service.ts
+++ b/backend/chatServer/src/room/room.service.ts
@@ -174,7 +174,7 @@ export class RoomService implements OnModuleInit, OnModuleDestroy {
     return await this.redisRepository.getUserBlacklist(roomId, address);
   }
 
-  async addUserToBlacklist(roomId: string, address: string, forwarded: string){
-    return await this.redisRepository.addUserBlacklistToRoom(roomId, address, forwarded);
+  async addUserToBlacklist(roomId: string, address: string, userAgent: string){
+    return await this.redisRepository.addUserBlacklistToRoom(roomId, address, userAgent);
   }
 }