Checking on Whether a Remote System is an Oracle Server

Nmap can be used to determine if a system is functioning as an Oracle server using the command nmap -p 1521 -P0 -sT <ip_address>. Port 1521 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?

References:

1. Which TCP/UDP port or ports does 'oracle' use?
   SecureTrust TCP/UDP Port Search Lookup Tool

[/network/Internet/IP/ports] permanent link

List-Update Script

Every month I receive a spreadsheet with a list of members in a retirees' organization. I extract the column in the spreadsheet containing the email addresses to a text file on a PC and then transfer it to a Solaris server that handles email addressed to the mailing list. I've been manually processing the text file each month to remove blank email addresses, duplicates, and invalid email addresses. At lunch today, I wrote a small BASH script, list-update to automate the process.

Since I don't use sed often, but sometimes need to use it to delete blank lines, such as the many that occur in the membership list, I thought I would put a note to myself here on the syntax for the sed command to remove blank lines from a file:

cat filename | sed -e '/^$/d' > newfilename

[/os/unix/programs/utilities] permanent link