Journey of Discovering Anomaly In Oracle Linux & 18cXE DB

Last week, I wanted to lay hands on latest incarnation of Oracle 18c Express Edition, a free version.

Unfortunately, not for Mac, available for selective flavours of Linux and Windows. I had Ubuntu 18.4 on VirtualBox, could not install easily. Gave up.

Thought of laying hands on AWS cloud, it comes with RDS Oracle service. However, it does not offers 18cXP out of box. Various other flavours, expensive licensed versions are supported.

Developer instinct prompted me to try on a raw EC2 instance of Oracle Linux 7 (based on Fedora).

Since both OS and Database are from same vendor, expected it to be smooth affair.

Alas a nightmare was waiting !

Started with VPC, with both private and public Subnets and a Security Group. Installation of Database was smooth as per the documentation, connection worked fine from within the same instance.

Real challenge emerged, when tried to connect to it from SQL Developer on my Mac or any other ec2. Tried all hacks to sort it, but of no avail.

As a debug strategy to get an insight of issue, tried another instance of RHEL with an older, 11g version of XE worked.

After trials and changes, realised some firewall like issue, is preventing traffic from other hosts post installation of Oracle 18c XE.

Finally after manipulating firewall to allow traffic on specific port, could make it work!

Here’s the command for same:

// Assuming port # is 1521, similarly to allow access to EM and APEX, we may have to open ports 5500 and 8080 (or whatever configured)

sudo firewall-cmd –permanent –zone=public –add-port=1521/tcp
sudo firewall-cmd –reload

Installation of this version or database on OL, modifies firewall,

https://oracle-base.com/articles/linux/linux-firewall#iptables

Please feel free to share your experiences.

Happy Explorations

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