I have a Forms 6i application. It retrieves data from a remote location and if there is no network connectivity, an error is generated and users cannot work.
I need to ping the remote location and check if the connection is available and if it is not available, take data from a local table and display on the form.
Thanks.
Use HOST built-in. It lets you execute an operating system command (which PING is).
Related
I'm trying to install Oracle Database for the first time and I'm facing many problem. I, following this guide, but I can't understand what should I set in the form shown in section 14. What is the database hostname? How I determine it?
It is described right above the section 14's screenshot:
The host name must resolve to the local host or virtual host because
the host name is used for the local Oracle WebLogic Server as well as
the Oracle Management Service. Do not provide a remote host or a load
balancer virtual host in this field. Do not enter an IP address. Do
not use underscores in the name. Short names are allowed, but you will
see a warning, so Oracle recommends that you enter a fully qualified
domain name instead.
I am trying to execute one simple desktop application in my system that is built upon java swing.
This application fetches the data from the oracle database which is present in computer A.
I did the development in computer A and built its jar and kept the jar in another system.
I have started all the services of oracle and created an ad hoc network between the two systems, but I am not able to execute the application from another computer. I googled a lot and did the mentioned changes. Still I am getting the same error of TNS listener.
IOException: The network adapter could not establish the connection.
finally I thought to put my code here. please look at the below code:
Class.forName("oracle.jdbc.driver.OracleDriver");
Connection connection =
DriverManager.getConnection("jdbc:oracle:thin:#//xxx.xxx.xxx.xxx:1521/XE"
,"system"
,"system" );
Please help me on this.
I have also tried modifying the tnsnames.ora file but was not helpful. can anybody please help me on this.
Check the listener.ora file - what is the IP address the service is binding to, i.e. what is the IP address specified in this file? If 127.0.0.1, that will explain why it works on Computer A but not B.
If this is the case you should fist stop teh listener service, backup the listener.ora, edit listener.ora, changing the IP address to the appropriate one for Computer A (accessible from Computer B), restart the listener, and retry.
Use tnsping to test the connection works, if you don't have TNS ping you can try "Telnet hostname port" (e.g. telnet computer-A 1521) and if it returns blank screen and flashing cursor on top left then the service is up.
I have a program consisting of a server and a client processes. Both run on Windows systems - Windows 2000 or later versions. The two processes can run on the same machine or on two different machines.
How can the client determine if it is run on the same machine as the server? If the server is not running the client can't work anyway and doesn't care where the server possibly is - so this case is out of the question. I've heard that each Windows machine has an UUID - can I obtain it and use for that purpose?
Windows networking requires computer names to be unique, so calling the GetComputerName api and having the client and server swap names (and compare the received name to the name they see) should suffice. If the client and server can start up independently of one another then you'll need some sort of protocol for this process. It seems logical for the client to initiate the exchange, and the server to only send its name when it has received a name from a client. The client can then abort the connection if it sees the same name.
I believe most virtual machine systems will allow the virtual machine to have its own name, so it should still be possible for you to test on virtual machines. However I don't have extensive experience of all the virtualisation technologies out there, so can't say for sure.
Previous question about generating a unique machine id that might help.
Link to previous answer which mentions MachineGUID
It is straightforward to add an API to the server that reports its machine name. The environment variable is COMPUTERNAME. The client could check that, right?
Do you need to deal with any of these cases?
The client is running, but the server is not responding, and you want to know whether the unresponsive server is on a remote machine.
The client and the server are running in two distinct virtual machines on the same host machine, and you want to report that as "running on the same machine."
The client is running in a virtual machine hosted by the same machine as the server is running on, and you want to report that as "running on the same machine."
The client and the server are running on uncoordinated networks and both might have been assigned the same name.
The server is possibly hostile, and will attempt to deceive the client.
The network card will have a unique MAC. If both server and client report the same MAC then they are using the same network card. If both client and server are running in different virtual machines but using the same network card, do you consider them running on the same machine or different machines?
how about trying to establish a loopback tcp connection? or maybe checking for some lock file created by the server in a predefined folder...
I don't know exactly how, but there's for sure something equivalent in Win32 to the /proc filesystem in Unix (I think there are free replacements for the windows taskmanager, maybe you could look at their sources) where you could search for your server process.
We have oracle 10g running on windows server 2003. A machine which runs an application using that database has as of a few weeks ago suddenly started having connectivity problems. Today we ran the automatic updates for windows server and the problem has only gotten worse. I realize this isn't enough information for anyone to diagnose the problem but perhaps you can get me pointed in the right direction with the following more specific scenario:
From this machine we can ping the server with absolutely no problem and, being physically close and on an intranet the return is very fast.
However, when we run tnsping I have seen 3 different results within a few minutes of each other.
tnsping returns just fine and in a reasonable amount of time
tnsping returns but only after a real long time (several seconds)
tnsping results in an ora-12560 protocol adapter error
At the same time I can tnsping the server from my machine with no problem.
Can anyone point me in the right direction?
I'd try to check the following:
do traceroute from the app server and from your machine check for anything abnormal
check tnsping from various other machine and try to identify a pattern
try a tcp/ip sniffer to see what is going on at both ends of the connection
get oracle support involved
To help eliminate DNS issues from the equation, specify the host's IP address in the TNSNAMES.ora file for your connection instead of a hostname. Are you using DHCP?
Have you eliminated hardware as the problem - have you tried a different NIC?
Before calling Oracle, I would create a trace file for a Fail case.
TNSPING.TRACE_LEVEL
Purpose
Use the parameter TNSPING.TRACE_LEVEL to turn TNSPING utility tracing on, at a specific level, or off.
Default
off
Values
* off: for no trace output
* user: for user trace information
* admin: for administration trace information
* support: for Oracle Support Services trace information
Example
TNSPING.TRACE_LEVEL=admin
Before involving oracle in this issue, get some help from your network administrator for the following test. First enable verbose logging on the database in the listener. Enable logging on the client via sqlnet. Go to the machine that is having trouble with tnsping, have the network administrator run a network tool to trace tcp packets from there. Perform the tnsping and see if what packet are being sent, what dns lookup are being made, what route is being taken. On the database see if the listener actually receives a ping from the client. If not then see where along the network to the database the problem is. Is it nameserver resolution? Is it a bad network cable, bad switch port, etc. Your network admin is your best friend for this problem. Do the same test via sqlplus with a simple connection and see what the client is logging.
Make sure there is no other machine on the network with the same IP address. A method would be unplug your machine from the network and see if you can still ping it. If you can then this is the problem.
If the server doesn't have a domain-name setup at a dns server, then add it's ip address and name to the host file on the server; this (the server not being able to find itself in dns) has been known to cause tns timeouts.
What steps do I need to take to change an IP address for Oracle 10g? I cannot connect to the database after going from a dhcp address to a static IP and a reboot.
If the server's IP address changed, these are the first things I would look at:
The TNSNAMES.ORA file on the client -- does it have the IP address hardcoded? If so, change it. Does it use the machine name? If so, does the machine name resolve to the correct IP address on your client machine?
The LISTENER.ORA file on the server -- does it explicitly specify the old IP address as its listening address?
More info please. Do you mean that you have changed the ip address of the host that the database is on and now you have to connect to it from a different macine, or are you having trouble starting the database after the ip change?
... and what error message do you receive?
Most obvious files to check are:
$ORACLE_HOME/network/admin/tnsnames.ora
$ORACLE_HOME/network/admin/listener.ora
Other than that we'd need more info...
I presume you mean the Oracle 10g DB and not the Oracle 10g Application Server?
Does the database start ok?
Is there anything in the database alert log?
Are the error(s) connecting from a client or the server?
What error message(s) do you get?
Can you ping the machine on it's new address (by both name + IP address) From both client + server?
Does a TNSPING work?
Can you connect using SQL*Plus on the server?
What other tool(s) have you tried connecting with?
Update after comment
Please can you post...
Your old ip address (if you know it)
Your new ip address
Your FQDN (e.g. machine.domain.com)
The output of "ipconfig/all" (or equivalent)
Your listener.ora file
The output of "$ORACLE_HOME/bin/lsnrctl start"
The output of "$ORACLE_HOME/bin/lsnrctl status"
Check that LOCAL_LISTENER is not defined (or defined correctly) in the database - it may not be registering correctly because of an incorrect entry here. Also try 'ALTER SYSTEM REGISTER' to attempt to register with the listener (rather than waiting up to 3 minutes for an auto-register). Examine the listener.log to see the instance registered (service_update * ) and 'lsnrctl status' to see if it is there.
Did you change the hostname in DNS? Can you ping the hostname from another machine?