The key to restoring a connectivity issue between the servers is knowing how to diagnose the network connection. We have put together a few simple steps that will help you diagnose the network connectivity and identify the issue.
Before diving deeper into programmatic configurations, please check if the principal condition is met:
1. It is important that the connection to the hostnames s1.m2epro.com (22.214.171.124) and s2.m2epro.com (126.96.36.199) is allowed. Often, the hostnames would need to be added to the firewall rules so that the server configurations would not block outgoing traffic to M2E server.
Once confirmed that the connection is not disrupted by any server settings, it’s worth verifying a few more points:
2. Using MTR program, you can diagnose the quality of the connection between the servers. The tool will let you observe the latency and overall performance of the network connectivity. The diagnostics will show if there are any packet losses which could be a potential cause of an unstable connection.
3. Checking performance of a DNS server may also help a lot to investigate the network connection problems. For example, DIG (Domain Information Groper) tool could be used to query information about various DNS records.
4. Finally, it is important to keep SSL CA certificates updated. Some connectivity issues may result from an outdated cURL library version or invalid certificates which are no longer supported. For example, M2E server does not support SSLv3 certificate due to its insecurity and vulnerability to attacks.