diff --git a/G-Earth/src/main/java/gearth/protocol/hostreplacer/ipmapping/LinuxIpMapper.java b/G-Earth/src/main/java/gearth/protocol/hostreplacer/ipmapping/LinuxIpMapper.java
index e5427a4..fe116e9 100644
--- a/G-Earth/src/main/java/gearth/protocol/hostreplacer/ipmapping/LinuxIpMapper.java
+++ b/G-Earth/src/main/java/gearth/protocol/hostreplacer/ipmapping/LinuxIpMapper.java
@@ -11,15 +11,15 @@ public class LinuxIpMapper extends IpMapper {
     @Override
     public void addMapping(String ip, int listenport, int connectport) {
         runCommand("iptables", "-t", "nat", "-A", "OUTPUT",
-                "-p", "all", "-d", ip, "--dport", listenport+"", "-j", "DNAT",
-                "--to-destination", "127.0.0.1:"+connectport);
+                "-p", "tcp", "-d", ip, "-j", "DNAT",
+                "--to-destination", "127.0.0.1");
     }
 
     @Override
     public void deleteMapping(String ip, int listenport, int connectport) {
         runCommand("iptables", "-t", "nat", "-D", "OUTPUT",
-                "-p", "all", "-d", ip, "--dport", listenport+"", "-j", "DNAT",
-                "--to-destination", "127.0.0.1:"+connectport);
+                "-p", "tcp", "-d", ip, "-j", "DNAT",
+                "--to-destination", "127.0.0.1");
     }
 
     @Override