diff --git a/bin/as.sh b/bin/as.sh
index f9ac4a321..1e8c8dc76 100755
--- a/bin/as.sh
+++ b/bin/as.sh
@@ -88,17 +88,20 @@ ARTHAS_LIB_DIR=${HOME}/.arthas/lib
 # target process id to attach
 TARGET_PID=
 
-# target process id to attach
-TARGET_IP="127.0.0.1"
+# target process id to attach, default 127.0.0.1
+TARGET_IP=
+DEFAULT_TARGET_IP="127.0.0.1"
 
-# telnet port
-TELNET_PORT="3658"
+# telnet port, default 3658
+TELNET_PORT=
+DEFAULT_TELNET_PORT="3658"
 
-# http port
-HTTP_PORT="8563"
+# http port, default 8563
+HTTP_PORT=
+DEFAULT_HTTP_PORT="8563"
 
 # telnet session timeout seconds, default 1800
-SESSION_TIMEOUT=1800
+SESSION_TIMEOUT=
 
 # use specify version
 USE_VERSION=
@@ -466,6 +469,33 @@ find_listen_port_process()
     fi
 }
 
+getTargetIPOrDefault()
+{
+    local targetIP=${DEFAULT_TARGET_IP}
+    if [ "${TARGET_IP}" ]; then
+        targetIP=${TARGET_IP}
+    fi
+    echo $targetIP
+}
+
+getTelnetPortOrDefault()
+{
+    local telnetPort=${DEFAULT_TELNET_PORT}
+    if [ "${TELNET_PORT}" ]; then
+        telnetPort=${TELNET_PORT}
+    fi
+    echo $telnetPort
+}
+
+getHttpPortOrDefault()
+{
+    local httpPort=${DEFAULT_HTTP_PORT}
+    if [ "${HTTP_PORT}" ]; then
+        httpPort=${HTTP_PORT}
+    fi
+    echo $httpPort
+}
+
 # Status from com.taobao.arthas.client.TelnetConsole
 # Execute commands timeout
 STATUS_EXEC_TIMEOUT=100
@@ -484,8 +514,8 @@ find_listen_port_process_by_client()
 
     "${JAVA_HOME}/bin/java" ${ARTHAS_OPTS} ${JVM_OPTS} \
              -jar "${arthas_lib_dir}/arthas-client.jar" \
-             ${TARGET_IP} \
-             ${TELNET_PORT} \
+             $(getTargetIPOrDefault) \
+             $(getTelnetPortOrDefault) \
              -c "session" \
              --execution-timeout 2000 \
              2>&1
@@ -647,16 +677,18 @@ parse_arguments()
     # check telnet port/http port
     local telnetPortPid
     local httpPortPid
-    if [[ $TELNET_PORT > 0 ]]; then
-        telnetPortPid=$(find_listen_port_process $TELNET_PORT)
+    local telnetPortOrDefault=$(getTelnetPortOrDefault)
+    local httpPortOrDefault=$(getHttpPortOrDefault)
+    if [[ $telnetPortOrDefault > 0 ]]; then
+        telnetPortPid=$(find_listen_port_process $telnetPortOrDefault)
         if [ $telnetPortPid ]; then
-            echo "[INFO] Process $telnetPortPid already using port $TELNET_PORT"
+            echo "[INFO] Process $telnetPortPid already using port $telnetPortOrDefault"
         fi
     fi
-    if [[ $HTTP_PORT > 0 ]]; then
-        httpPortPid=$(find_listen_port_process $HTTP_PORT)
+    if [[ $httpPortOrDefault > 0 ]]; then
+        httpPortPid=$(find_listen_port_process $httpPortOrDefault)
         if [ $telnetPortPid ]; then
-            echo "[INFO] Process $httpPortPid already using port $HTTP_PORT"
+            echo "[INFO] Process $httpPortPid already using port $httpPortOrDefault"
         fi
     fi
 
@@ -727,7 +759,7 @@ parse_arguments()
             exit 1
         fi
         if [[ ($httpPortPid) && ($TARGET_PID != $httpPortPid) ]]; then
-            echo "Target process $TARGET_PID is not the process using port $HTTP_PORT, you will connect to an unexpected process."
+            echo "Target process $TARGET_PID is not the process using port $(getHttpPortOrDefault), you will connect to an unexpected process."
             echo "1. Try to restart as.sh, select process $httpPortPid, shutdown it first with running the 'stop' command."
             echo "2. Try to use different http port, for example: as.sh --telnet-port 9998 --http-port 9999"
             exit 1
@@ -774,14 +806,27 @@ attach_jvm()
         tempArgs+=("${APP_NAME}")
     fi
 
+    if [ "${TARGET_IP}" ]; then
+        tempArgs+=("-target-ip")
+        tempArgs+=("${TARGET_IP}")
+    fi
+    if [ "${TELNET_PORT}" ]; then
+        tempArgs+=("-telnet-port")
+        tempArgs+=("${TELNET_PORT}")
+    fi
+    if [ "${HTTP_PORT}" ]; then
+        tempArgs+=("-http-port")
+        tempArgs+=("${HTTP_PORT}")
+    fi
+    if [ "${SESSION_TIMEOUT}" ]; then
+        tempArgs+=("-session-timeout")
+        tempArgs+=("${SESSION_TIMEOUT}")
+    fi
+
     "${java_command[@]}" \
         ${ARTHAS_OPTS} ${JVM_OPTS} \
         -jar "${arthas_lib_dir}/arthas-core.jar" \
             -pid ${TARGET_PID} \
-            -target-ip ${TARGET_IP} \
-            -telnet-port ${TELNET_PORT} \
-            -http-port ${HTTP_PORT} \
-            -session-timeout ${SESSION_TIMEOUT} \
             "${tempArgs[@]}" \
             -core "${arthas_lib_dir}/arthas-core.jar" \
             -agent "${arthas_lib_dir}/arthas-agent.jar"
@@ -826,7 +871,7 @@ sanity_check() {
 }
 
 port_pid_check() {
-    if [[ $TELNET_PORT > 0 ]]; then
+    if [[ $(getTelnetPortOrDefault) > 0 ]]; then
         local telnet_output
         local find_process_status
         # declare local var before var=$()
@@ -859,15 +904,15 @@ port_pid_check() {
 }
 
 print_telnet_port_pid_error() {
-    echo "[ERROR] The telnet port $TELNET_PORT is used by process $telnetPortPid instead of target process $TARGET_PID, you will connect to an unexpected process."
+    echo "[ERROR] The telnet port $(getTelnetPortOrDefault) is used by process $telnetPortPid instead of target process $TARGET_PID, you will connect to an unexpected process."
     echo "[ERROR] 1. Try to restart as.sh, select process $telnetPortPid, shutdown it first with running the 'stop' command."
-    echo "[ERROR] 2. Try to stop the existing arthas instance: java -jar arthas-client.jar 127.0.0.1 $TELNET_PORT -c \"stop\""
+    echo "[ERROR] 2. Try to stop the existing arthas instance: java -jar arthas-client.jar 127.0.0.1 $(getTelnetPortOrDefault) -c \"stop\""
     echo "[ERROR] 3. Try to use different telnet port, for example: as.sh --telnet-port 9998 --http-port -1"
 }
 
 print_telnet_port_used_error() {
     local error_msg=$1
-    echo "[ERROR] The telnet port $TELNET_PORT is used, but process $error_msg, you will connect to an unexpected process."
+    echo "[ERROR] The telnet port $(getTelnetPortOrDefault) is used, but process $error_msg, you will connect to an unexpected process."
     echo "[ERROR] Try to use different telnet port, for example: as.sh --telnet-port 9998 --http-port -1"
 }
 
@@ -896,16 +941,16 @@ active_console()
         if [ "${COMMAND}" ] ; then
         "${JAVA_HOME}/bin/java" ${ARTHAS_OPTS} ${JVM_OPTS} \
              -jar "${arthas_lib_dir}/arthas-client.jar" \
-             ${TARGET_IP} \
-             ${TELNET_PORT} \
+             $(getTargetIPOrDefault) \
+             $(getTelnetPortOrDefault) \
              "${tempArgs[@]}" \
              -c "${COMMAND}"
         fi
         if [ "${BATCH_FILE}" ] ; then
         "${JAVA_HOME}/bin/java" ${ARTHAS_OPTS} ${JVM_OPTS} \
              -jar "${arthas_lib_dir}/arthas-client.jar" \
-             ${TARGET_IP} \
-             ${TELNET_PORT} \
+             $(getTargetIPOrDefault) \
+             $(getTelnetPortOrDefault) \
              "${tempArgs[@]}" \
              -f ${BATCH_FILE}
         fi
@@ -914,12 +959,12 @@ active_console()
         if [[ $(command -v telnet) == *"system32"* ]] ; then
             # Windows/system32/telnet.exe can not run in Cygwin/MinGw
             echo "It seems that current bash is under Windows. $(command -v telnet) can not run under bash."
-            echo "Please start cmd.exe from Windows start menu, and then run telnet ${TARGET_IP} ${TELNET_PORT} to connect to target process."
-            echo "Or visit http://127.0.0.1:${HTTP_PORT} to connect to target process."
+            echo "Please start cmd.exe from Windows start menu, and then run telnet $(getTargetIPOrDefault) $(getTelnetPortOrDefault) to connect to target process."
+            echo "Or visit http://127.0.0.1:$(getHttpPortOrDefault) to connect to target process."
             return 1
         fi
         echo "telnet connecting to arthas server... current timestamp is `date +%s`"
-        telnet ${TARGET_IP} ${TELNET_PORT}
+        telnet $(getTargetIPOrDefault) $(getTelnetPortOrDefault)
     else
         echo "'telnet' is required." 1>&2
         return 1
diff --git a/boot/src/main/java/com/taobao/arthas/boot/Bootstrap.java b/boot/src/main/java/com/taobao/arthas/boot/Bootstrap.java
index 1573e4ac1..502d7c2c3 100644
--- a/boot/src/main/java/com/taobao/arthas/boot/Bootstrap.java
+++ b/boot/src/main/java/com/taobao/arthas/boot/Bootstrap.java
@@ -67,9 +67,9 @@ public class Bootstrap {
     private boolean help = false;
 
     private long pid = -1;
-    private String targetIp = DEFAULT_TARGET_IP;
-    private int telnetPort = DEFAULT_TELNET_PORT;
-    private int httpPort = DEFAULT_HTTP_PORT;
+    private String targetIp;
+    private Integer telnetPort;
+    private Integer httpPort;
     /**
      * @see com.taobao.arthas.core.config.Configure#DEFAULT_SESSION_TIMEOUT_SECONDS
      */
@@ -333,16 +333,16 @@ public class Bootstrap {
         // check telnet/http port
         long telnetPortPid = -1;
         long httpPortPid = -1;
-        if (bootstrap.getTelnetPort() > 0) {
-            telnetPortPid = SocketUtils.findTcpListenProcess(bootstrap.getTelnetPort());
+        if (bootstrap.getTelnetPortOrDefault() > 0) {
+            telnetPortPid = SocketUtils.findTcpListenProcess(bootstrap.getTelnetPortOrDefault());
             if (telnetPortPid > 0) {
-                AnsiLog.info("Process {} already using port {}", telnetPortPid, bootstrap.getTelnetPort());
+                AnsiLog.info("Process {} already using port {}", telnetPortPid, bootstrap.getTelnetPortOrDefault());
             }
         }
-        if (bootstrap.getHttpPort() > 0) {
-            httpPortPid = SocketUtils.findTcpListenProcess(bootstrap.getHttpPort());
+        if (bootstrap.getHttpPortOrDefault() > 0) {
+            httpPortPid = SocketUtils.findTcpListenProcess(bootstrap.getHttpPortOrDefault());
             if (httpPortPid > 0) {
-                AnsiLog.info("Process {} already using port {}", httpPortPid, bootstrap.getHttpPort());
+                AnsiLog.info("Process {} already using port {}", httpPortPid, bootstrap.getHttpPortOrDefault());
             }
         }
 
@@ -365,7 +365,7 @@ public class Bootstrap {
 
         if (httpPortPid > 0 && pid != httpPortPid) {
             AnsiLog.error("Target process {} is not the process using port {}, you will connect to an unexpected process.",
-                            pid, bootstrap.getHttpPort());
+                            pid, bootstrap.getHttpPortOrDefault());
             AnsiLog.error("1. Try to restart arthas-boot, select process {}, shutdown it first with running the 'stop' command.",
                             httpPortPid);
             AnsiLog.error("2. Or try to use different http port, for example: java -jar arthas-boot.jar --telnet-port 9998 --http-port 9999", httpPortPid);
@@ -469,10 +469,10 @@ public class Bootstrap {
         AnsiLog.info("arthas home: " + arthasHomeDir);
 
         if (telnetPortPid > 0 && pid == telnetPortPid) {
-            AnsiLog.info("The target process already listen port {}, skip attach.", bootstrap.getTelnetPort());
+            AnsiLog.info("The target process already listen port {}, skip attach.", bootstrap.getTelnetPortOrDefault());
         } else {
             //double check telnet port and pid before attach
-            telnetPortPid = findProcessByTelnetClient(arthasHomeDir.getAbsolutePath(), bootstrap.getTelnetPort());
+            telnetPortPid = findProcessByTelnetClient(arthasHomeDir.getAbsolutePath(), bootstrap.getTelnetPortOrDefault());
             checkTelnetPortPid(bootstrap, telnetPortPid, pid);
 
             // start arthas-core.jar
@@ -481,12 +481,21 @@ public class Bootstrap {
             attachArgs.add(new File(arthasHomeDir, "arthas-core.jar").getAbsolutePath());
             attachArgs.add("-pid");
             attachArgs.add("" + pid);
-            attachArgs.add("-target-ip");
-            attachArgs.add(bootstrap.getTargetIp());
-            attachArgs.add("-telnet-port");
-            attachArgs.add("" + bootstrap.getTelnetPort());
-            attachArgs.add("-http-port");
-            attachArgs.add("" + bootstrap.getHttpPort());
+            if (bootstrap.getTargetIp() != null) {
+                attachArgs.add("-target-ip");
+                attachArgs.add(bootstrap.getTargetIp());
+            }
+
+            if (bootstrap.getTelnetPort() != null) {
+                attachArgs.add("-telnet-port");
+                attachArgs.add("" + bootstrap.getTelnetPort());
+            }
+
+            if (bootstrap.getHttpPort() != null) {
+                attachArgs.add("-http-port");
+                attachArgs.add("" + bootstrap.getHttpPort());
+            }
+
             attachArgs.add("-core");
             attachArgs.add(new File(arthasHomeDir, "arthas-core.jar").getAbsolutePath());
             attachArgs.add("-agent");
@@ -546,10 +555,10 @@ public class Bootstrap {
         }
 
         // telnet port ,ip
-        telnetArgs.add(bootstrap.getTargetIp());
-        telnetArgs.add("" + bootstrap.getTelnetPort());
+        telnetArgs.add(bootstrap.getTargetIpOrDefault());
+        telnetArgs.add("" + bootstrap.getTelnetPortOrDefault());
 
-        AnsiLog.info("arthas-client connect {} {}", bootstrap.getTargetIp(), bootstrap.getTelnetPort());
+        AnsiLog.info("arthas-client connect {} {}", bootstrap.getTargetIpOrDefault(), bootstrap.getTelnetPortOrDefault());
         AnsiLog.debug("Start arthas-client.jar args: " + telnetArgs);
 
         // fix https://github.com/alibaba/arthas/issues/833
@@ -560,10 +569,10 @@ public class Bootstrap {
     private static void checkTelnetPortPid(Bootstrap bootstrap, long telnetPortPid, long targetPid) {
         if (telnetPortPid > 0 && targetPid != telnetPortPid) {
             AnsiLog.error("The telnet port {} is used by process {} instead of target process {}, you will connect to an unexpected process.",
-                    bootstrap.getTelnetPort(), telnetPortPid, targetPid);
+                    bootstrap.getTelnetPortOrDefault(), telnetPortPid, targetPid);
             AnsiLog.error("1. Try to restart arthas-boot, select process {}, shutdown it first with running the 'stop' command.",
                             telnetPortPid);
-            AnsiLog.error("2. Or try to stop the existing arthas instance: java -jar arthas-client.jar 127.0.0.1 {} -c \"stop\"", bootstrap.getTelnetPort());
+            AnsiLog.error("2. Or try to stop the existing arthas instance: java -jar arthas-client.jar 127.0.0.1 {} -c \"stop\"", bootstrap.getTelnetPortOrDefault());
             AnsiLog.error("3. Or try to use different telnet port, for example: java -jar arthas-boot.jar --telnet-port 9998 --http-port -1");
             System.exit(1);
         }
@@ -712,14 +721,38 @@ public class Bootstrap {
         return targetIp;
     }
 
-    public int getTelnetPort() {
-        return telnetPort;
+    public String getTargetIpOrDefault() {
+        if (this.targetIp == null) {
+            return DEFAULT_TARGET_IP;
+        } else {
+            return this.targetIp;
+        }
     }
 
-    public int getHttpPort() {
+    public Integer getTelnetPort() {
+        return telnetPort;
+    }
+    
+    public int getTelnetPortOrDefault() {
+        if (this.telnetPort == null) {
+            return DEFAULT_TELNET_PORT;
+        } else {
+            return this.telnetPort;
+        }
+    }
+
+    public Integer getHttpPort() {
         return httpPort;
     }
 
+    public int getHttpPortOrDefault() {
+        if (this.httpPort == null) {
+            return DEFAULT_HTTP_PORT;
+        } else {
+            return this.httpPort;
+        }
+    }
+
     public String getCommand() {
         return command;
     }
diff --git a/common/src/main/java/com/taobao/arthas/common/ArthasConstants.java b/common/src/main/java/com/taobao/arthas/common/ArthasConstants.java
index 44c75eceb..94947905d 100644
--- a/common/src/main/java/com/taobao/arthas/common/ArthasConstants.java
+++ b/common/src/main/java/com/taobao/arthas/common/ArthasConstants.java
@@ -14,7 +14,7 @@ public class ArthasConstants {
      */
     public static final String NETTY_LOCAL_ADDRESS = "arthas-netty-LocalAddress";
 
-    public static int MAX_HTTP_CONTENT_LENGTH = 1024 * 1024 * 8;
+    public static final int MAX_HTTP_CONTENT_LENGTH = 1024 * 1024 * 8;
 
     public static final String ARTHAS_OUTPUT = "arthas-output";
 
@@ -22,4 +22,6 @@ public class ArthasConstants {
 
     public static final String PROJECT_NAME = "project.name";
     public static final String SPRING_APPLICATION_NAME = "spring.application.name";
+
+    public static final int TELNET_PORT = 3658;
 }
diff --git a/core/src/main/java/arthas.properties b/core/src/main/java/arthas.properties
index 8a906de63..a33df8167 100644
--- a/core/src/main/java/arthas.properties
+++ b/core/src/main/java/arthas.properties
@@ -1,7 +1,10 @@
 #arthas.config.overrideAll=true
 arthas.telnetPort=3658
 arthas.httpPort=8563
-arthas.ip=localhost
+arthas.ip=127.0.0.1
+
+# seconds
+arthas.sessionTimeout=1800
 
 #arthas.tunnelServer=ws://127.0.0.1:7777/ws
 #arthas.agentId=mmmmmmyiddddd
diff --git a/core/src/main/java/com/taobao/arthas/core/Arthas.java b/core/src/main/java/com/taobao/arthas/core/Arthas.java
index b53b920b9..1d282870e 100644
--- a/core/src/main/java/com/taobao/arthas/core/Arthas.java
+++ b/core/src/main/java/com/taobao/arthas/core/Arthas.java
@@ -22,9 +22,6 @@ import java.util.Properties;
  */
 public class Arthas {
 
-    private static final String DEFAULT_TELNET_PORT = "3658";
-    private static final String DEFAULT_HTTP_PORT = "8563";
-
     private Arthas(String[] args) throws Exception {
         attachAgent(parse(args));
     }
@@ -35,11 +32,11 @@ public class Arthas {
         Option agent = new TypedOption<String>().setType(String.class).setShortName("agent").setRequired(true);
         Option target = new TypedOption<String>().setType(String.class).setShortName("target-ip");
         Option telnetPort = new TypedOption<Integer>().setType(Integer.class)
-                .setShortName("telnet-port").setDefaultValue(DEFAULT_TELNET_PORT);
+                .setShortName("telnet-port");
         Option httpPort = new TypedOption<Integer>().setType(Integer.class)
-                .setShortName("http-port").setDefaultValue(DEFAULT_HTTP_PORT);
+                .setShortName("http-port");
         Option sessionTimeout = new TypedOption<Integer>().setType(Integer.class)
-                        .setShortName("session-timeout").setDefaultValue("" + Configure.DEFAULT_SESSION_TIMEOUT_SECONDS);
+                        .setShortName("session-timeout");
 
         Option tunnelServer = new TypedOption<String>().setType(String.class).setShortName("tunnel-server");
         Option agentId = new TypedOption<String>().setType(String.class).setShortName("agent-id");
@@ -55,15 +52,20 @@ public class Arthas {
         configure.setJavaPid((Long) commandLine.getOptionValue("pid"));
         configure.setArthasAgent((String) commandLine.getOptionValue("agent"));
         configure.setArthasCore((String) commandLine.getOptionValue("core"));
-        configure.setSessionTimeout((Integer)commandLine.getOptionValue("session-timeout"));
-        if (commandLine.getOptionValue("target-ip") == null) {
-            throw new IllegalStateException("as.sh is too old to support web console, " +
-                    "please run the following command to upgrade to latest version:" +
-                    "\ncurl -sLk https://arthas.aliyun.com/install.sh | sh");
+        if (commandLine.getOptionValue("session-timeout") != null) {
+            configure.setSessionTimeout((Integer) commandLine.getOptionValue("session-timeout"));
+        }
+
+        if (commandLine.getOptionValue("target-ip") != null) {
+            configure.setIp((String) commandLine.getOptionValue("target-ip"));
+        }
+
+        if (commandLine.getOptionValue("telnet-port") != null) {
+            configure.setTelnetPort((Integer) commandLine.getOptionValue("telnet-port"));
+        }
+        if (commandLine.getOptionValue("http-port") != null) {
+            configure.setHttpPort((Integer) commandLine.getOptionValue("http-port"));
         }
-        configure.setIp((String) commandLine.getOptionValue("target-ip"));
-        configure.setTelnetPort((Integer) commandLine.getOptionValue("telnet-port"));
-        configure.setHttpPort((Integer) commandLine.getOptionValue("http-port"));
 
         configure.setTunnelServer((String) commandLine.getOptionValue("tunnel-server"));
         configure.setAgentId((String) commandLine.getOptionValue("agent-id"));
diff --git a/core/src/main/java/com/taobao/arthas/core/config/Configure.java b/core/src/main/java/com/taobao/arthas/core/config/Configure.java
index f3b03c7e3..c0982b01b 100644
--- a/core/src/main/java/com/taobao/arthas/core/config/Configure.java
+++ b/core/src/main/java/com/taobao/arthas/core/config/Configure.java
@@ -17,11 +17,11 @@ import static java.lang.reflect.Modifier.isStatic;
  */
 @Config(prefix = "arthas")
 public class Configure {
-    public static final long DEFAULT_SESSION_TIMEOUT_SECONDS = ShellServerOptions.DEFAULT_SESSION_TIMEOUT/1000;
+
     private String ip;
-    private int telnetPort;
-    private int httpPort;
-    private long javaPid;
+    private Integer telnetPort;
+    private Integer httpPort;
+    private Long javaPid;
     private String arthasCore;
     private String arthasAgent;
 
@@ -43,8 +43,9 @@ public class Configure {
 
     /**
      * session timeout seconds
+     * @see ShellServerOptions#DEFAULT_SESSION_TIMEOUT
      */
-    private long sessionTimeout = DEFAULT_SESSION_TIMEOUT_SECONDS;
+    private Long sessionTimeout;
 
     public String getIp() {
         return ip;
@@ -54,7 +55,7 @@ public class Configure {
         this.ip = ip;
     }
 
-    public int getTelnetPort() {
+    public Integer getTelnetPort() {
         return telnetPort;
     }
 
@@ -66,7 +67,7 @@ public class Configure {
         this.httpPort = httpPort;
     }
 
-    public int getHttpPort() {
+    public Integer getHttpPort() {
         return httpPort;
     }
 
@@ -94,7 +95,7 @@ public class Configure {
         this.arthasCore = arthasCore;
     }
 
-    public long getSessionTimeout() {
+    public Long getSessionTimeout() {
         return sessionTimeout;
     }
 
diff --git a/core/src/main/java/com/taobao/arthas/core/server/ArthasBootstrap.java b/core/src/main/java/com/taobao/arthas/core/server/ArthasBootstrap.java
index ad44cf86c..058244e76 100644
--- a/core/src/main/java/com/taobao/arthas/core/server/ArthasBootstrap.java
+++ b/core/src/main/java/com/taobao/arthas/core/server/ArthasBootstrap.java
@@ -285,12 +285,12 @@ public class ArthasBootstrap {
         }
 
         // init random port
-        if (configure.getTelnetPort() == 0) {
+        if (configure.getTelnetPort() != null && configure.getTelnetPort() == 0) {
             int newTelnetPort = SocketUtils.findAvailableTcpPort();
             configure.setTelnetPort(newTelnetPort);
             logger().info("generate random telnet port: " + newTelnetPort);
         }
-        if (configure.getHttpPort() == 0) {
+        if (configure.getHttpPort() != null && configure.getHttpPort() == 0) {
             int newHttpPort = SocketUtils.findAvailableTcpPort();
             configure.setHttpPort(newHttpPort);
             logger().info("generate random http port: " + newHttpPort);
@@ -322,8 +322,10 @@ public class ArthasBootstrap {
         try {
             ShellServerOptions options = new ShellServerOptions()
                             .setInstrumentation(instrumentation)
-                            .setPid(PidUtils.currentLongPid())
-                            .setSessionTimeout(configure.getSessionTimeout() * 1000);
+                            .setPid(PidUtils.currentLongPid());
+            if (configure.getSessionTimeout() != null) {
+                options.setSessionTimeout(configure.getSessionTimeout() * 1000);
+            }
 
             if (agentId != null) {
                 Map<String, String> welcomeInfos = new HashMap<String, String>();
diff --git a/core/src/main/java/com/taobao/arthas/core/shell/term/TermServer.java b/core/src/main/java/com/taobao/arthas/core/shell/term/TermServer.java
index af5ab912b..dde1f3633 100644
--- a/core/src/main/java/com/taobao/arthas/core/shell/term/TermServer.java
+++ b/core/src/main/java/com/taobao/arthas/core/shell/term/TermServer.java
@@ -1,5 +1,6 @@
 package com.taobao.arthas.core.shell.term;
 
+import com.taobao.arthas.common.ArthasConstants;
 import com.taobao.arthas.core.config.Configure;
 import com.taobao.arthas.core.shell.ShellServerOptions;
 import com.taobao.arthas.core.shell.future.Future;
@@ -20,7 +21,8 @@ public abstract class TermServer {
      * @return the term server
      */
     public static TermServer createTelnetTermServer(Configure configure, ShellServerOptions options) {
-        return new TelnetTermServer(configure.getIp(), configure.getTelnetPort(), options.getConnectionTimeout());
+        int port = configure.getTelnetPort() != null ? configure.getTelnetPort() : ArthasConstants.TELNET_PORT;
+        return new TelnetTermServer(configure.getIp(), port, options.getConnectionTimeout());
     }
 
     /**