diff --git a/fe/fe-core/src/main/java/org/apache/doris/system/FQDNManager.java b/fe/fe-core/src/main/java/org/apache/doris/system/FQDNManager.java
index 2f60d3b2b5ec99..e86e2b76a46cd0 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/system/FQDNManager.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/system/FQDNManager.java
@@ -34,6 +34,8 @@
 public class FQDNManager extends MasterDaemon {
     private static final Logger LOG = LogManager.getLogger(FQDNManager.class);
 
+    public static final String UNKNOWN_HOST_IP = "unknown";
+
     private SystemInfoService nodeMgr;
 
     public FQDNManager(SystemInfoService nodeMgr) {
@@ -64,6 +66,13 @@ private void updateFeIp() {
                     }
                 } catch (UnknownHostException e) {
                     LOG.warn("unknown host name for fe, {}", fe.getHostName(), e);
+                    // add fe alive check to make ip work when fe is still alive and dns has some problem.
+                    if (!fe.isAlive() && !fe.getIp().equalsIgnoreCase(UNKNOWN_HOST_IP)) {
+                        String ip = fe.getIp();
+                        fe.setIp(UNKNOWN_HOST_IP);
+                        Env.getCurrentEnv().getEditLog().logModifyFrontend(fe);
+                        LOG.warn("ip for {} of fe has been changed from {} to {}", fe.getHostName(), ip, "unknown");
+                    }
                 } catch (DdlException e) {
                     LOG.warn("fail to update ip for fe, {}", fe.getHostName(), e);
                 }
@@ -85,6 +94,14 @@ private void updateBeIp() {
                     }
                 } catch (UnknownHostException e) {
                     LOG.warn("unknown host name for be, {}", be.getHostName(), e);
+                    // add be alive check to make ip work when be is still alive and dns has some problem.
+                    if (!be.isAlive() && !be.getIp().equalsIgnoreCase(UNKNOWN_HOST_IP)) {
+                        String ip = be.getIp();
+                        ClientPool.backendPool.clearPool(new TNetworkAddress(ip, be.getBePort()));
+                        be.setIp(UNKNOWN_HOST_IP);
+                        Env.getCurrentEnv().getEditLog().logBackendStateChange(be);
+                        LOG.warn("ip for {} of be has been changed from {} to {}", be.getHostName(), ip, "unknown");
+                    }
                 }
             }
         }
diff --git a/fe/fe-core/src/main/java/org/apache/doris/system/SystemInfoService.java b/fe/fe-core/src/main/java/org/apache/doris/system/SystemInfoService.java
index abb08dcb961d08..1b10fd28334257 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/system/SystemInfoService.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/system/SystemInfoService.java
@@ -192,10 +192,6 @@ public void addBackends(List<HostInfo> hostInfos, boolean isFree)
     public void addBackends(List<HostInfo> hostInfos, boolean isFree, String destCluster,
             Map<String, String> tagMap) throws UserException {
         for (HostInfo hostInfo : hostInfos) {
-            //if not enable_fqdn,ignore hostName
-            if (!Config.enable_fqdn_mode) {
-                hostInfo.setHostName(null);
-            }
             if (Config.enable_fqdn_mode && StringUtils.isEmpty(hostInfo.getHostName())) {
                 throw new DdlException("backend's hostName should not be empty while enable_fqdn_mode is true");
             }