This topic provides a list of hints that can help you figure out why the device list of the address book mode shows a particular DS (address book entry) with "no response" or "unknown device" status. See troubleshooting (auto-discovery mode) and troubleshooting (COM mode) for hints on other two access modes.
In the address book access mode you do not encounter a situation when you cannot "see" some entries in the device list. This is because this list is created manually by you and all address book entries are displayed at all times, even when corresponding Device Servers cannot be reached. Instead, you often have to solve the problem of why the DS Manager cannot contact the DS specified in the particular address book entry.
The problem can manifest itself in two different ways:
|---||The DS Manager indicates that there is no response from the IP-address specified in the address book entry (no status icon is displayed at all).|
|The DS Manager indicates that there is some kind of device at the specified IP-address but it doesn't seem to be a Tibbo Device Server (the question mark is displayed).|
"No response" status is displayed when the DS Manager cannot PING the IP-address specified in the address book entry.
Here is why you may get "no response" status:
|•||The DS may be switched off or not connected to the network*.|
|•||Incorrect IP-address may be specified for this address book entry. Think carefully what IP-address you input. Depending on the router setup you may need to input the IP-address of the DS itself or the access (forwarding) IP-address on the router**.|
|•||Firewall software on your PC or on the router may be set to disallow PINGs (a very common situation on many networks). For the DS Manager to work you must have PING (ICMP) traffic enabled. Attention here! Our experience shows that many Users are not aware of the firewall software installed on their own PCs! Some firewalls come as part of larger "protection" suites (anti-virus, anti-intrusion, etc. programs). Some operating systems, such as Windows XP, include the firewall software too.|
|•||If your DS is running an older firmware (V2.xx) then it will not be accessible through the network and won't respond to PINGs in the following cases:|
|When the DS is in the error mode (status LEDs of the DS "play" the pattern as shown on the left)**.|
This does not apply to the Device Servers running DS firmware V3.xx or higher. In this firware the DS is visible on the network at all times.
"Unknown device" status is displayed when there is no reply to the echo command sent by the DS Manager. This command is unique to Tibbo Device Servers and is used to identify them on the network (and also collect status information). Depending on the access method specified for this address book entry the echo command may be sent as out-of-band UDP commandor inband TCP command.
Here is why you may get "unknown device" status:
|•||If out-of-band (UDP) access method is selected for this address book entry:|
|•||In certain cases this may be because the DS is switched off or not connected to the network. It is true that if the DS Manager displays the icon this means that it has already got the reply to the PING request but in some router modes the PING reply actually comes from the router, not the DS itself**. Therefore, do make sure that the DS is online;|
|•||Incorrect programming port number may be specified for this address book entry. Think carefully what port number you input. Depending on the router setup you may need to input the command port number on the DS itself (i.e. 65535 or 32767, you can use either one) or the access (forwarding) port on the router**;|
|•||Firewall software on your PC or on the router may be set to disallow UDP traffic (a very common situation on many networks). For the DS Manager to work you must enable UDP traffic to the command port specified in this address book entry. In some router setups** UDP traffic through the router is very unreliable or completely impossible. In this case you may need to use inband access method which relies on TCP protocol.|
|•||If inband TCP access method is selected for this address book entry:|
|•||First of all remember, that for "inband" address book entries the DS Manager does not automatically verify DS presence when the Refresh button is pressed. Therefore, after the Refresh button is clicked all Device Servers for which the inband access is defined initially appear in the list with the icon. If you want to check if such a DS is accessible then attempt to execute the desired action: press Settings button or Buzz button and see the result (upgrade, initialize, and routing status functions are not available for "inband" address book entries). At this point the DS Manager will attempt to establish a TCP connection to the DS and find out if the DS is accessible. This will be reflected in the device list. |
|•||Incorrect programming port number may be specified for this address book entry. Think carefully what port number you input. Depending on the router setup you may need to input the data port number on the DS itself (this is the port number specified by the Data Port Number (PN) setting of the DS) or the access (forwarding) port on the router**;|
|•||The DS may be already engaged in a data TCP connection with another application and/or network host. Since inband commands are, by definition, the commands that are passed within the data connection itself the DS Manager actually establishes a data TCP connection with the DS in order to program it (this is why this connection is made to the data port of the DS, not the command port). The DS only allows for a single data connection at a time, so if it is already engaged in a data connection with another application and/or network host the DS Manager will be rejected***.|
|•||If telnet TCP access method is selected for this address book entry:|
|•||Telnet TCP access method is only supported by newer Device Servers running firmware V3.50 or higher. Make sure you are not attempting to use this access method for the Device Server that doesn't support it;|
|•||Incorrect programming port number may be specified for this address book entry. Think carefully what port number you input. Depending on the router setup you may need a standard telnet port of 23 or some other access (forwarding) port on the router**. |
* Really sorry for this "hint"... it's just that this is the root cause of the problem in many cases!
** Here we touch on a very complicated subject. Modern routers offer a bewildering array of setup options. We will attempt to cover this in details in our upcoming white papers.
*** We understand that this is a limitation and are working to remove it.