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Connectivity

Purpose: Resolve network and connectivity issues.

Contents - External Access Issues - Service Communication - Database Connectivity - Cache Connectivity - Sources

External Access Issues

Symptom: Cannot access Firefly III from browser

Issue Symptom Diagnosis Solution Source
Connection refused Browser can't reach site Service not running or port blocked Check service status and firewall "Firefly III Installation" — https://docs.firefly-iii.org/how-to/firefly-iii/installation/self-hosted/ — retrieved 2025-01-09
502 Bad Gateway Nginx shows 502 error PHP-FPM not responding Restart application container "Nginx Troubleshooting" — ops/docker/nginx/ — retrieved 2025-01-09
Slow loading Pages load very slowly Resource exhaustion or network issues Check container resources and network "Performance Guide" — docs/techdocs/ops/troubleshooting/performance.md — retrieved 2025-01-09

Diagnostic Commands: 

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# Test external connectivity
curl -v http://localhost:8080/

# Check port binding
netstat -tulpn | grep :8080

# Test from different network
curl -v http://$(hostname -I | awk '{print $1}'):8080/

# Check firewall status
sudo ufw status verbose

Service Communication

Inter-container communication issues:

Service Pair Error Diagnosis Solution Source
App → Database Connection refused Network or service issue Check container network and database health "Docker Networking" — docker-compose.yml — retrieved 2025-01-09
App → Redis Redis timeout Redis not responding Verify Redis container status "Redis Configuration" — ops/docker/redis/ — retrieved 2025-01-09
Nginx → App 502/504 errors PHP-FPM not responding Check application container logs "Nginx Configuration" — ops/docker/nginx/ — retrieved 2025-01-09

Service Communication Tests: 

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# Test database connectivity from app
docker exec firefly-iii-application.application nc -zv firefly-iii-application.mariadb 3306

# Test Redis connectivity from app
docker exec firefly-iii-application.application nc -zv firefly-iii-application.redis 6379

# Test app connectivity from nginx
docker exec firefly-iii-application.nginx nc -zv firefly-iii-application.application 9000

# Check container network
docker network inspect webgrip

Database Connectivity

Common database connection issues:

Issue Symptom Resolution Source
Max connections reached "Too many connections" Increase max_connections or fix connection leaks "MariaDB Tuning" — https://mariadb.com/kb/en/server-system-variables/#max_connections — retrieved 2025-01-09
Connection timeout Queries hang Check wait_timeout and interactive_timeout "MariaDB Configuration" — ops/docker/mariadb/ — retrieved 2025-01-09
Authentication failure Access denied Verify credentials and host permissions "Database Setup" — docs/techdocs/app/integrations/database.md — retrieved 2025-01-09

Cache Connectivity

Redis connection troubleshooting:

Issue Symptom Resolution Source
Memory full Redis OOM errors Increase memory limit or implement eviction "Redis Memory" — https://redis.io/docs/manual/eviction/ — retrieved 2025-01-09
Connection drops Intermittent failures Check tcp-keepalive settings "Redis Configuration" — ops/docker/redis/ — retrieved 2025-01-09
Slow responses High latency Monitor Redis performance metrics "Cache Performance" — docs/techdocs/app/integrations/cache.md — retrieved 2025-01-09

Sources