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Question I've installed NPort/NE series Driver properly, but why can not my application program (AP) open ports successfully?
Question Type Application
Updated 4/1/2008 3:34:05 PM
Hits 29395
Products NPort 5230 Series,NPort Express DE-211,NPort Express DE-311,NPort 5210/NPort 5230/NPort 5232 Series,NPort 5410/NPort 5430/NPort 5450 Series,NPort 5430 Series,NPort 5610/NPort 5630 Series,NE-4100T,NE-4110S,NE-4110A,NPort 5110/NPort 5130/NPort 5150 Series,NE-4120S,NE-4120A,NPort Server Lite DE-301/302/304/331/332/334,NPort DE-311M



1. Improper IP configuration.

2. Improper OP_mode .

3. DHCP issue.

4. Access authorization.

5. COM port No. conflicts with other devices.

6. Your firewall filter rule discards the specific TCP packet.

7. DE-311/211 has a DIP SW1 setting error.

8. Port is occupied.

9. Forget to click 'Apply' and 'Save' button.


  • Make sure that your Host is able to PING the NPort.
  • Your operation mode must be [ Host Based / Driver Mode] or [Real COM Mode].
  • If your Host and NPort are in DHCP environment :
    a) You have to assign a fixed IP address to NPort & your Host.
    b) Under DHCP environment, you can map a specific IP address to your NPort's & Host's MAC address.
  • Use NPort Configurator or Administrator to check the NPort's access control list; your Host IP must exist in NPort's access control list.
  • Check if there is any other installation using the same COM port number,
    e.g., internal modem on COM3.
  • Check filter rules to open TCP port # 950(to 965) & # 966(to 981).
  • The DE-311/211's DIP SW1 must be OFF for data communication.
  • Telnet NPort's IP address, and check the ''Conn. Status'' message under [Monitor]. It must be set to ''listen'' before you open the port.
  • Please remember click 'Apply' button after setting COM Mapping with NPort5000/NE series. And click 'Save' button after installing Driver with NPort Server Family .

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