Worldline Bambora Terminal: 502 Error Diagnostic - Solar... | terminalfaults.org

Technical Background:

A 502 error implies the terminal's TCP/IP communication with the payment gateway is failing. Root causes include incorrect DNS resolution, firewall rules blocking port 443 (HTTPS), or VPN configuration causing routing conflicts. Signal attenuation due to cable quality or external interference (EMI/ESD) may also contribute to intermittent connectivity.

Symptoms:

The Worldline Bambora terminal displays a 502 error after recent changes to the server's VPN settings. This indicates a 'Bad Gateway' response, suggesting the terminal cannot reliably communicate with the payment processing server.

Possible Causes:

VPN configuration conflict: The terminal's traffic is not correctly routed through the new VPN, or multiple VPNs are interfering with each other.
Firewall restrictions: The payment gateway's IP address or port 443 is blocked by the local firewall following the VPN change.
Incorrect DNS settings: The terminal is unable to resolve the payment gateway's hostname to its IP address.
Cable or network hardware failure: A faulty Ethernet cable or network switch is causing intermittent connectivity.
IP address conflict: The terminal or another device on the network is using a conflicting IP address.
TLS/SSL handshake failure: The terminal and payment gateway are unable to establish a secure connection due to mismatched or outdated TLS/SSL protocols/certificates.

Solution:

1

Safe Handling: Unplug the terminal from the power source.
2

Verify Network Connectivity: Use a separate device (laptop) on the same network to test connectivity to the payment gateway's IP address (if known) or hostname using ping and traceroute commands. If inaccessible, the issue is network-wide.
3

Review VPN Configuration: Ensure the VPN configuration allows the terminal's traffic to reach the payment gateway. Consult the VPN provider or IT administrator.
4

Check Firewall Rules: Verify that the firewall is not blocking the terminal's access to the payment gateway on port
5

Open port 443 if necessary (Consult with IT).
6

Confirm DNS Settings: Ensure the terminal is using the correct DNS servers. Typically, these are provided by the network's DHCP server. Manually configured DNS settings may be incorrect.
7

Inspect Cables and Connections: Check the Ethernet cable connecting the terminal to the network. Replace if damaged. Ensure all connections are secure.
8

Reboot the Terminal: After confirming network settings, reconnect the terminal to the power source and allow it to reboot. This may resolve temporary connectivity issues.

Safety Warning:

Do not attempt to open the terminal casing. Doing so will trigger the internal anti-tamper mechanisms and permanently disable the device. Safe Handling: Always unplug the terminal before inspecting cables or connections. Avoid operating the terminal in excessively humid or dusty environments.

Prevention:

Regularly inspect Ethernet cables for damage and ensure they are securely connected. Avoid cable strain by using proper cable management. Clean the touchscreen with a dry, lint-free cloth to prevent electrostatic discharge (ESD) during dry conditions. Review firewall and VPN configurations after any network changes.

Expert Tip:

If the terminal uses a static IP address, try switching it to DHCP to automatically obtain an IP address from the network. This can resolve IP address conflicts. A temporary outage of the payment processor server itself can cause 502 errors - check status pages.

Frequently Asked Questions

•What VPN client is in use?

Client-specific settings are critical.

•What is the network topology?

Understanding the network path aids troubleshooting.

•Is the terminal's clock synchronized?

Incorrect time can cause TLS/SSL errors.

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What VPN client is in use?

•What is the network topology?

•Is the terminal's clock synchronized?

Related questions

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Solution:

Safety Warning:

Prevention:

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