In this Document

Applies to:

Symptoms

During Cluster Verification, a part of cluster installation, the connectivity check between nodes may fail with the following errors

Check: TCP connectivity of subnet "10.0.0.0"
Source                         Destination                    Connected?
------------------------------ ------------------------------ ----------------
racnode01:10.0.0.1             racnode02:10.0.0.2             failed

ERROR:
PRVF-7617 : Node connectivity between "racnode01 : 10.0.0.1" and "racnode02 : 10.0.0.2" failed
Result: TCP connectivity check failed for subnet "10.0.0.0"

 This may occur on any of the interface.

Cause

iptables (a Linux firewall) is active between the nodes, blocking network traffic on the cluster interconnect network.

Solution

1. A temporary solution is to disable iptables. A more permanent soution, if iptables is required, is to configure the iptables such that it does not block interconnect traffic(no firewall should exist between cluster nodes).

To disable iptables, use the following commands as root:

For IPV4:

For IPV6:

Note: IPV6 is not supported with Oracle Clusterware/RAC 11gR2

2. If SElinux is set to enforcing, change it to permissive or disable could help too.

To check what mode the system is running:

Temporary switchoff enforcement, as root user:

This will switch to permissive mode, no reboot is required.

To permanently switchoff enforcement, edit /etc/selinux/config, change SELINUX to either "permissive" or "disabled". A server reboot is required if change SELINUX to "disabled".

References