Still Cannot Connect to Ports XXXX Even After Adding to VCN Security Rules and IPTables Rules

Applies To:

Oracle Cloud Infrastructure - Version N/A and later

Linux x86-64

Symptoms:

Connections to certain ports still fail even when they are allowed in VCN security list/rules, and are also added to IPTables rules for target ACCEPT.

In this particular example, TCP ports 5500 and 5501 are intended to be open to traffic, but are still blocked.

[root@client ~]# nc -4v <server_ip> 5500
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connection timed out.
[root@client ~]#
[root@client ~]# nc -4v <server_ip> 5501
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connection timed out.
[root@client ~]#

Changes:

Added TCP ports 5500 and 5501 to VCN security list/rules.