Default security settings differ for each Linux OS distribution and may require additional configuration to allow connections to the required ports.
NOTE: Starting with Veeam Backup & Replication 10, the traffic port range was reduced from 2500-5000 to 2500-3300. The new port range only applies to newly deployed components after Veeam Backup & Replication 10 is installed. If an environment was upgraded from a version of Veeam Backup & Replication before 10, all existing components that were managed before the upgrade will continue to use 2500-5000.
If connections to a Linux server fail, ensure that the Linux server does not have firewall restrictions for ports 2500-3300.
If the distro uses UFW or FirewallD, remove the IPTables entry used for testing after troubleshooting is completed and integrate the ports rule into the firewall solution.
Example of Firewall wall rule configuration using iptables: