tnsnames.org set up

this is actually from another thread, but, got off topic...below question is one response from sumit2906:
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ok, working on figuring out how to fill in tnsnames.ora. Doesn't seem like devleoper connection info maps to the tns:
developer connection info is:
Connection Name: Tst Srvr1 (that's just an alias, right?)
user: xxx
password: xxx
role: default, connection type: LDAP, OS Authentication Kerberow Auth. and Proxy Conn. not checked
LDAP Server: oid.xxx.com:123:456   (not sure what this is)
DB Service: POST.xxx.com  (not sure what this is)

So, need to fill in tnsnames.ora
(ADDRESS = (PROTOCOL = TCP)     ---leave that as is?
(HOST = <hostname or IP>)   ---will oid.xxx.com:123:456 work?
(PORT = <port>)   ---no clue here
not sure on the following, except service might be POST.xxx.com
(CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = <database service name>)

then, does it matter wher this file is saved?
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In your case, it will be like this:
tstsrvr1 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = <hostname or IP>)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = POST.xxx.com)
    )
  )

you should be able to ping the hostname or IP, the default port is 1521, it could be different.
Also, the file location is fixed, it is under oracle_home\network\admin directory. You can also use command tnsping test to see where is it expecting the file.

The best way is to take the tns entry from your server machine, and use it.

Also, this is not a related question, so better to open a new question, that way you will get more responses.