Net 8 realted

dear Friends
I have question realted to net8. I am using oracle 8.1.6 on NT.
Which file Oracle serach when client requests connection with server?and why?

(1)Tnsname.ora on server
(2)Tnsname.ora on client
(3)Listener.ora on Server
(4)Listener.ora on client

Another query is what's differnce between
tnsname.ora and listener.ora file?

Tnsnames.ora is found on client and server sides. Listener.ora is only on the server side. So if you wanted to connect to the db, Oracle looks for tnsnames.ora on the client side and then tries to match it to the listener.ora on the server side.
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Tnsnames.ora contains the name of the db, port# and hostname/IP of te server. Listener.ora contains the same info. When these match, a connection is established.

When ever a client is invoked, it would look for the tnsnames.ora file to solve the service name.

i.e when you call sqlplus username@service_name the service name is resolved by the tnsnames.ora file. So every client and the server is supposed to have the tnsnames.ora file to resolve the service name.

Now coming to the listener.ora, when you call for a service, the tnsnames.ora would specify, the host that has the specified listener, that could provide the service. This is how the client would establish the service to the server.

client --> tnsnames. ora --> listener.ora --> database_instance

The listener would live on the server and you can have multiple listeners listening on different port serving the same instance.

I hope this would help you to undestand things, better.

Sam

Okk good Then what's use of tnsnames.ora on server side?

Thats if you want to open a SQL Plus sessiomn on the server side itself, rather than a client machine.

Quote:

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Originally posted by Halo
Thats if you want to open a SQL Plus sessiomn on the server side itself, rather than a client machine.

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Another common use of server side tnsnames.ora would be when a connection to a remote database should be established via database link. In this case the service name of the remote database is resolved with server's tnsnames.ora.

I would just like to add that listener.ora file doesn't play *any role* during any kind of database conection. The only time it is being used is when the listener is started, as it contains (almost) all the information about listener configuration.

HTH,

listener.ora on the server side.
tnsnames.ora on client side with connect string pointing to the related listener entry.
tnsnames.ora is searched for the server information but before that sqlnet.ora is read to find out the sequence of search that is whether it should first look in tnsnames.ora file, names server etc.
Also if Advanced Networking is option is installed then parameters related to that are matched with the server sqlnet.ora
Also the default domain is taken from sqlnet.ora .

Thanks
GP