How to Enable IPv6 on Oracle 19c: A Step‑by‑Step Guide

The article explains how to configure IPv6 on an Oracle Database 19c (version 19.7) running on Red Hat 7.6 with RAC enabled, addressing a client request to test simultaneous IPv4 and IPv6 connectivity.

1. Verify IPv6 is enabled on the OS

Two common methods are used:

Check the network interface attributes with ifconfig -a. If the output contains an inet6 entry, IPv6 is active.

Inspect loaded kernel modules using lsmod | grep ipv6. Presence of the ipv6 module confirms support.

2. Assign a static IPv6 address

The default address cannot be pinged, so a custom address is added to the network‑interface configuration file. The example adds two addresses—one primary and one backup:

# Example addition to /etc/sysconfig/network-scripts/ifcfg‑eth0
IPV6INIT=yes
IPV6_AUTOCONF=no
IPV6ADDR=2020:db8:1000::200/64
IPV6ADDR_SECONDARIES=2020:db8:1000::201/64

After saving the file, restart the network service and verify the new IPv6 address appears with ifconfig -a.

3. Update the Oracle listener for IPv6

The listener configuration must include an IPv6 address that differs from the IPv4 port. The original LISTENER parameter is:

LISTENER=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER))))

It is changed to:

LISTENER=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER))(ADDRESS=(PROTOCOL=TCP)(HOST=2020:db8:1000::200)(PORT=1601)(IP=FIRST))))

After editing listener.ora, restart the listener and confirm the new endpoint:

4. Test the IPv6 connection

Create a TNS entry that points to the IPv6 address and port, then use tnsping or a client tool to verify successful connection. Screenshots show a successful test.

5. Confirm the listener process opened the IPv6 socket

Inspect the files opened by the pmon process; the presence of an IPv6 socket indicates the listener is correctly bound.

With these steps, IPv6 is fully configured for Oracle 19c, and the database can accept both IPv4 and IPv6 client connections.