diff --git a/src/backend/chat-server/src/main/java/com/bbebig/chatserver/domain/chat/controller/ChannelEventController.java b/src/backend/chat-server/src/main/java/com/bbebig/chatserver/domain/chat/controller/ChannelEventController.java
index 9b56b548..12779432 100644
--- a/src/backend/chat-server/src/main/java/com/bbebig/chatserver/domain/chat/controller/ChannelEventController.java
+++ b/src/backend/chat-server/src/main/java/com/bbebig/chatserver/domain/chat/controller/ChannelEventController.java
@@ -2,6 +2,9 @@
 
 import com.bbebig.chatserver.domain.chat.repository.SessionManager;
 import com.bbebig.chatserver.domain.chat.service.KafkaProducerService;
+import com.bbebig.chatserver.global.util.SequenceRedisGenerator;
+import com.bbebig.commonmodule.global.response.code.error.ErrorStatus;
+import com.bbebig.commonmodule.global.response.exception.ErrorHandler;
 import com.bbebig.commonmodule.kafka.dto.ChannelEventDto;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import jakarta.validation.Valid;
@@ -26,12 +29,14 @@ public class ChannelEventController {
 
 	private final ObjectMapper objectMapper;
 
+	private final SequenceRedisGenerator sequenceRedisGenerator;
+
 	// 현재 보고있는 채널 변경 이벤트 처리
 	@MessageMapping("/channel/enter")
 	public void enterChannel(Message<?> message) throws IOException {
 		ChannelEventDto channelEventDto = extractChannelEventDto(message);
-		log.info("[Chat] ChannelEventController: 채널 입장 이벤트. memberId = {}, channelId = {}, sessionId = {}",
-				channelEventDto.getMemberId(), channelEventDto.getChannelId(), channelEventDto.getSessionId());
+		log.info("[Chat] ChannelEventController: 채널 입장 이벤트. memberId = {}, channelId = {}, sessionId = {}, channelEventDto = {}",
+				channelEventDto.getMemberId(), channelEventDto.getChannelId(), channelEventDto.getSessionId(), channelEventDto);
 		validateTimestamps(channelEventDto);
 		kafkaProducerService.sendMessageForChannel(channelEventDto);
 	}
@@ -40,9 +45,11 @@ public void enterChannel(Message<?> message) throws IOException {
 	@MessageMapping("/channel/leave")
 	public void leaveChannel(Message<?> message) throws IOException {
 		ChannelEventDto channelEventDto = extractChannelEventDto(message);
-		log.info("[Chat] ChannelEventController: 채널 퇴장 이벤트. memberId = {}, channelId = {}, sessionId = {}",
-				channelEventDto.getMemberId(), channelEventDto.getChannelId(), channelEventDto.getSessionId());
+		log.info("[Chat] ChannelEventController: 채널 퇴장 이벤트. memberId = {}, channelId = {}, sessionId = {}, channelEventDto = {}",
+				channelEventDto.getMemberId(), channelEventDto.getChannelId(), channelEventDto.getSessionId(), channelEventDto);
 		validateTimestamps(channelEventDto);
+
+		validateLastInfo(channelEventDto);
 		kafkaProducerService.sendMessageForChannel(channelEventDto);
 	}
 
@@ -54,6 +61,21 @@ private void validateTimestamps(ChannelEventDto channelEventDto) {
 		}
 	}
 
+	private void validateLastInfo(ChannelEventDto channelEventDto) {
+		if (channelEventDto.getLastReadMessageId() == null || channelEventDto.getLastReadSequence() == null) {
+			log.warn("[Chat] ChannelEventController: lastReadMessageId 또는 lastReadSequence 값이 null이므로 기본값으로 설정. memberId: {}, channelId: {}", channelEventDto.getMemberId(), channelEventDto.getChannelId());
+			Long seq = sequenceRedisGenerator.getSeqForServerChannel(channelEventDto.getChannelId());
+			if (seq != null) {
+				channelEventDto.setLastReadMessageId(seq);
+				channelEventDto.setLastReadSequence(seq);
+			} else {
+				log.error("[Chat] ChannelEventController: lastReadMessageId 또는 lastReadSequence 값이 null이고 Redis에서 시퀀스를 가져올 수 없음. memberId: {}, channelId: {}", channelEventDto.getMemberId(), channelEventDto.getChannelId());
+			}
+			channelEventDto.setLastReadMessageId(0L);
+			channelEventDto.setLastReadSequence(0L);
+		}
+	}
+
 	private ChannelEventDto extractChannelEventDto(Message<?> message) throws IOException {
 		StompHeaderAccessor headerAccessor = StompHeaderAccessor.wrap(message);
 
diff --git a/src/backend/chat-server/src/main/java/com/bbebig/chatserver/domain/chat/handler/StompHandler.java b/src/backend/chat-server/src/main/java/com/bbebig/chatserver/domain/chat/handler/StompHandler.java
index 61bbd20c..21c65396 100644
--- a/src/backend/chat-server/src/main/java/com/bbebig/chatserver/domain/chat/handler/StompHandler.java
+++ b/src/backend/chat-server/src/main/java/com/bbebig/chatserver/domain/chat/handler/StompHandler.java
@@ -14,7 +14,6 @@
 import org.springframework.messaging.simp.stomp.StompCommand;
 import org.springframework.messaging.simp.stomp.StompHeaderAccessor;
 import org.springframework.messaging.support.ChannelInterceptor;
-import org.springframework.messaging.support.MessageBuilder;
 import org.springframework.stereotype.Component;
 import org.springframework.web.context.WebApplicationContext;
 
@@ -94,7 +93,7 @@ public void postSend(Message<?> message, MessageChannel channel, boolean sent) {
 
 		StompCommand command = headerAccessor.getCommand();
 
-		log.info("[Chat] StompHandler Post send: sessionId={}, command={}", sessionId, command);
+		log.info("[Chat] StompHandler Post send: sessionId={}, command={}, memberId={}", sessionId, command, sessionManager.findMemberIdBySessionId(sessionId));
 
 		if (command == null) {
 			log.error("[Chat] StompHandler: postSend - command 정보 없음. 전체 헤더 정보: {}", headerAccessor.toMap());
@@ -102,6 +101,7 @@ public void postSend(Message<?> message, MessageChannel channel, boolean sent) {
 		}
 		if (StompCommand.CONNECT.equals(command)) {
 			Long memberId = Long.parseLong(Objects.requireNonNull(headerAccessor.getFirstNativeHeader("MemberId")));
+			log.info("[Chat] StompHandler Post send - CONNECT: sessionId={}, command={}, memberId={}", sessionId, command, memberId);
 			ConnectionEventDto connectionEventDto = ConnectionEventDto.builder()
 					.memberId(memberId)
 					.type(ConnectionEventType.CONNECT)
@@ -115,6 +115,7 @@ public void postSend(Message<?> message, MessageChannel channel, boolean sent) {
 					.build();
 
 			kafkaProducerService.sendMessageForSession(connectionEventDto);
+//			sessionManager.saveConnectSessionInfo(sessionId, memberId);
 		} else if (StompCommand.DISCONNECT.equals(command)) {
 			if (sessionId == null) {
 				log.error("[Chat] StompHandler: DISCONNECT 요청 시 세션 ID 없음");
diff --git a/src/backend/chat-server/src/main/java/com/bbebig/chatserver/global/config/WebSocketConfig.java b/src/backend/chat-server/src/main/java/com/bbebig/chatserver/global/config/WebSocketConfig.java
index af1df9f0..d41520a6 100644
--- a/src/backend/chat-server/src/main/java/com/bbebig/chatserver/global/config/WebSocketConfig.java
+++ b/src/backend/chat-server/src/main/java/com/bbebig/chatserver/global/config/WebSocketConfig.java
@@ -37,12 +37,15 @@ public void configureMessageBroker(MessageBrokerRegistry registry) {
 	@Override
 	public void registerStompEndpoints(StompEndpointRegistry registry) {
 
+		registry.addEndpoint("/ws-mobile") // 클라이언트가 연결할 엔드포인트 설정
+				.setAllowedOriginPatterns("*");
+
 		registry.addEndpoint("/ws-chat") // 클라이언트가 연결할 엔드포인트 설정
-				.setAllowedOrigins("*");
+				.setAllowedOriginPatterns("*");
 
 		// 웹소켓을 사용할 수 없는 환경에서 sockJS 지원
 		registry.addEndpoint("/ws-chat") // 클라이언트가 연결할 엔드포인트 설정
-				.setAllowedOrigins("*")
+				.setAllowedOriginPatterns("*")
 				.withSockJS();
 
 		registry.setErrorHandler(stompErrorHandler);
diff --git a/src/backend/chat-server/src/main/java/com/bbebig/chatserver/global/util/SequenceRedisGenerator.java b/src/backend/chat-server/src/main/java/com/bbebig/chatserver/global/util/SequenceRedisGenerator.java
index 5cacf2a6..96ef079f 100644
--- a/src/backend/chat-server/src/main/java/com/bbebig/chatserver/global/util/SequenceRedisGenerator.java
+++ b/src/backend/chat-server/src/main/java/com/bbebig/chatserver/global/util/SequenceRedisGenerator.java
@@ -23,5 +23,10 @@ public Long nextSeqForServerChannel(Long channelId) {
 		return redisSetTemplate.opsForValue().increment(redisKey);
 	}
 
+	public Long getSeqForServerChannel(Long channelId) {
+		String redisKey = ServerRedisKeys.getServerChannelSequenceKey(channelId);
+		return redisSetTemplate.opsForValue().get(redisKey);
+	}
+
 }
 
diff --git a/src/backend/common-module/src/main/java/com/bbebig/commonmodule/global/response/code/error/ErrorStatus.java b/src/backend/common-module/src/main/java/com/bbebig/commonmodule/global/response/code/error/ErrorStatus.java
index 85d751b0..02054c86 100644
--- a/src/backend/common-module/src/main/java/com/bbebig/commonmodule/global/response/code/error/ErrorStatus.java
+++ b/src/backend/common-module/src/main/java/com/bbebig/commonmodule/global/response/code/error/ErrorStatus.java
@@ -39,6 +39,7 @@ public enum ErrorStatus implements BaseErrorCode {
     CHAT_ROOM_NOT_FOUND(HttpStatus.BAD_REQUEST, "CHAT401", "채팅방이 존재하지 않습니다."),
     CHAT_ROOM_ALREADY_EXIST(HttpStatus.BAD_REQUEST, "CHAT402", "이미 존재하는 채팅방입니다."),
     CHAT_ROOM_MEMBER_NOT_FOUND(HttpStatus.BAD_REQUEST, "CHAT403", "채팅방에 참여한 멤버가 존재하지 않습니다."),
+    CHANNEL_LEAVE_LAST_INFO_NOT_VALID(HttpStatus.BAD_REQUEST, "CHAT404", "채널 퇴장 시 마지막 정보가 유효하지 않습니다."),
 
     // SERVICE
     SERVER_NOT_FOUND(HttpStatus.NOT_FOUND, "SERVICE401", "서버를 찾을 수 없습니다."),
diff --git a/src/backend/common-module/src/main/java/com/bbebig/commonmodule/kafka/dto/ChatMessageDto.java b/src/backend/common-module/src/main/java/com/bbebig/commonmodule/kafka/dto/ChatMessageDto.java
index c3fe055c..8b0fb318 100644
--- a/src/backend/common-module/src/main/java/com/bbebig/commonmodule/kafka/dto/ChatMessageDto.java
+++ b/src/backend/common-module/src/main/java/com/bbebig/commonmodule/kafka/dto/ChatMessageDto.java
@@ -49,11 +49,9 @@ public class ChatMessageDto {
 	private List<Long> targetMemberIds; // 메시지 대상자 목록 (DM일 경우)
 
 	// CREATE 시 필요
-	@PastOrPresent(message = "생성 시간은 현재 시간 이전이어야 합니다.")
 	private LocalDateTime createdAt;
 
 	// UPDATE 시 필요
-	@PastOrPresent(message = "수정 시간은 현재 시간 이전이어야 합니다.")
 	private LocalDateTime updatedAt;
 
 	// @JsonCreator와 @JsonProperty를 사용한 생성자