Our application must be able to send notifications via MQTT to our partners. When the partner submits an item, we create a new topic which they then subscribe to.
Problem: They regularly need to re-subscribe to the topic to keep receiving messages.
Testing: We tried to reproduce using the same client (MQTTX) and same client configuration but we continued to receive messages when it stopped on their side.
Additional info:
- The broker is hosted on a server protected by a firewall, it is configured to only let through requests from our and their VPN.
- We are unable to edit the firewall configuration as it is hosted by OVH and we don't have the credentials.
Technologies:
- Broker: ActiveMQ
- Clients: reproduced on their side using both MQTTX and their own client
Broker configuration:
policyEntry.setAlwaysRetroactive(true);
policyEntry.setSubscriptionRecoveryPolicy(new LastImageSubscriptionRecoveryPolicy());
I don't expect anyone to provide a solution only based on what I was able to write here, but only to give some directions which could help us understand what's happening and why.