Checking on Whether a Remote System is an Oracle Server
can be used to determine if
a system is functioning as an Oracle server using the command
nmap -p 1521 -P0 -sT <ip_address>
is a port used by
Oracle server software, but the port may also be used by other software,
so, if nmap reports the system is listening on that port, it does not
guarantee that the system is an Oracle server.
The options specified above are as follows:
-p <port ranges>
This option specifies what ports you want to query.
-P0 Do not try and ping hosts at all before scanning them. This
allows the scanning of networks that don't allow ICMP echo
requests (or responses) through their firewall.
-sT TCP connect() scan: This is the most basic form of TCP scanning.
The connect() system call provided by your operating system is
used to open a connection to every interesting port on the
machine. If the port is listening, connect() will succeed,
otherwise the port isn't reachable. One strong advantage to this
technique is that you don/t need any special privileges. Any
user on most UNIX boxes is free to use this call.
For a list of other ports used by Oracle, you can check
Which TCP/UDP port or ports does 'oracle' use?
Which TCP/UDP port or ports does 'oracle' use?
SecureTrust TCP/UDP Port Search Lookup Tool
Determining the Country Associated with an IP Address
You can use GeoIP to look up the country associated with a given IP
address (you can also give it a hostname to determine the country).
To create the GeoIP program geoiplookup, you can download the
C source code from
You will need a C compiler to compile the code. If you intend to use it on a
Linux or Unix system, you will have a C compiler on the system, so just
follow the instructions below to create the geoiplookup program or read the
INSTALL file that comes with the file you download from the MaxMind website.
If you intend to install it on a Windows system, read the READMEwin32.txt
file that is in the .gz file you download.
Unzip the downloaded file, extract the contents of the resultant
tar file and then change the working directory to the GeoIP directory
created from the contents of the tar file.
tar -xvf GeoIP-1.3.6.tar
Then run the
(installation instructions are in the INSTALL file created in the GeoIP
directory, but are also summarized here).
You can then issue the command
make check to run self-tests of
the package, but this step isn't required. You should then type
make install to install the software.
At this point you won't need the program binaries and other files in
the source code directory and they can be removed with
clean. You can also remove the files created by
by issuing the command
make distclean. You can also remove the
GeoIP directory and its contents, if you wish, since
installs the package's files in /usr/local/bin, /usr/local/man, etc.
rm -fr GeoIP-1.3.6
When the program is installed, you will have a geoiplookup program in
/usr/local/bin. You can use that program to lookup the country associated
with an IP address or hostname. The country is based on the registration
for the IP address, i.e. particular blocks of IP addresses will be associated
with particular countries or at least areas of the world. The company
using the IP address may be based in some other country, however. For
GeoIP Country Edition: US, United States
The company has their website, eapplique.com, hosted on a server with
a US IP address. But if you issue the command
eapplique.com, you will see the domain
name is registered to a company in India (the company provides website
design services). So geoiplookup gives you an indication of where a
server is likely to be located, but not necessarily the location of a
particular company using that server. Companies and individuals may
use servers located in other countries.
THE SCS GROUP (EAPPLIQUE-DOM)
K 3/17, DLF Phase II
GURGAON, HARYANA 122002
Domain Name: EAPPLIQUE.COM
For an example of a lookup for an IP address, here is another example:
GeoIP Country Edition: HK, Hong Kong
Determining Your IP Address
If you need to determine the IP address systems on the Internet
will see as your address, you can go to any of the following sites:
- Canadian Web Solutions
(click on the Quick-Find link)
Keep in mind that address is not necessarily the IP address assigned
to your computer if you are on a Local Area Network (LAN). If you are
behind a firewall or a router performing Network Address Translation
(NAT), your locally assigned address may differ from the address
websites and other servers on the Internet see as your originating
address. If your router is performing NAT, there may be multiple
computers behind the router with unique IP addresses, but the
router may have ony one outside IP address. The router keeps track
of which connections are associated with which inside IP addresses.
You can determine your system's actual address by going to
What is my IP Address?.
Or if you are using a PC running Windows by getting a command prompt
by clicking on Start, Run, and then typing command
and hitting enter. Then type ipconfig, which will show you
your IP address, your subnet mask, and the default gateway address, which
is the address of the system, e.g. a router, that your system would use
to gain access to the Internet. On a Linux system, if you are logged
on as root, you can type ifconfig -a, then look for the "inet addr"
value, which will usually be associated with the eth0 interface. The
l0 interface is a "loopback" address of 127.0.0.1, which is just an
address that allows a system to communicate with itself.