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Enterprise Manager and Firewalls

Just a short post, since this is a fairly common question I see. This morning someone asked me a question about Enterprise Manager and firewalls. They have an environment with EM targets placed in different zones / networks – with firewalls between. In the documentation, it states “Each Management Agent is configured to upload data to one OMS. As a result, if there is a firewall between the Management Agent and its OMS, you must configure the firewall to allow the Management Agent to upload data to the OMS using the upload URL.”

and then further

Keep your orapw password file secure

This is a small demo I did when I’ve found a database password file (orapw) lying around in /tmp with -rw-rw-rw- permissions, to show how this is a bad idea. People think that the orapw file only contains hashes to validate a password given, and forget that it can be used to connect to a remote database without password.

I can easily imagine why the orapwd was there in /tmp. To build a standby database, you need to copy the password file to the standby server. If you don’t have direct access to the oracle user, but only a sudo access for ‘security reasons’, you can’t scp easily. Then you copy the file to /tmp, make it readable by all users, and you can scp with your user.

In this demo I don’t even have access to the host. I’ve only access to connect to a PDB with the SCOTT users, reated with utlsampl.sql, with those additional privileges, a read access on $ORACLE_HOME/dbs:

ODBVv2 – ghostdata busters

Some time ago I wrote a simple tool to learn about Oracle data block internals – ODBV.
The series of articles can be found here: and the github repo is here:

This is not a production tool but during the last session in Birmingham at UKOUG_TECH17 – where I was doing a presentation using this tool – I came to the conclusion that with a little bit of work it could be used to trace ghost data in a database.

What is ghost data? This is very simple – each time we delete something or truncate or move, Oracle database is not removing data from our datafile – the blocks are "marked" for reuse and are not associated with any logical object in a database, but our data is still there.

Shooting the DBA isn’t a Silver Bullet to the Cloud

We’ve all been watching numerous companies view value in bypassing the Database Administrator and other critical IT roles in an effort to get IT faster to the cloud.  It may look incredibly attractive to sales, but the truth of it is, it can be like setting up land mines in your own yard.

The Security State of the Nation

Even though my social media profile is pretty available for Twitter and Linked in, I’m significantly conservative with other personal and financial data online.  The reversal of the Internet Privacy Rule, (I’ve linked to a Fox news link, as there was so much negative news on this one…) had everyone pretty frustrated, but then we need to look at security of personal information, especially financial data and as we can see by security breaches so far in 2017, we all have reason to be concerned.

Quick tip–database link passwords

If you are relying on database links in your application, think carefully about how you want to manage the accounts that you connect with, in particular, when it comes to password expiry.

With a standard connect request to the database, if your password is going to expire soon, you will get some feedback on this:

SQL> conn demo/demo@np12
ORA-28002: the password will expire within 6 days


But when using those same credentials via a database link, you will not get any warning, so when that password expires…you might be dead in the water.

orapwd gives OPW-00029 Password complexity failed in #Oracle 12.2 600w, htt

A performance deep dive into column encryption

Actually, this is a follow up post from my performance deep dive into tablespace encryption. After having investigated how tablespace encryption works, this blogpost is looking at the other encryption option, column encryption. A conclusion that can be shared upfront is that despite they basically perform the same function, the implementation and performance consequences are quite different.

Oracle database (januari 2017 PSU) and TDE wallets

Recently, I was trying to setup TDE. Doing that I found out the Oracle provided documentation isn’t overly clear, and there is a way to do it in pre-Oracle 12, which is done using ‘alter system’ commands, and a new-ish way to do it in Oracle 12, using ‘administer key management’ commands. I am using version, so decided to use the ‘administer key management’ commands. This blogpost is about an exception which I see is encountered in the Januari 2017 (170117) PSU of the Oracle database, which is NOT happening in Oracle 12.2 (no PSU’s for Oracle 12.2 at the time of writing) and Oracle April 2016 and October 2016 PSU’s.

In order to test the wallet functionality for TDE, I used the following commands:

Better to be safe than sorry…

I’ve always been worried about taking a script that is fine to run in my non-production environments (in particular a DROP script) and accidentally running it in a Production environment, shortly followed by the typing up of a fresh resume to look for a new job once the mistake is discovered Smile