Troubleshooting Common iScan Server Issues — Quick FixesiScan Server is a powerful tool for network scanning, device management, and centralized security monitoring. Even well-designed systems encounter problems. This article walks through common iScan Server issues, how to diagnose them, and quick fixes to get your system back online with minimal downtime. Each section includes root-cause checks, step-by-step fixes, and tips to prevent recurrence.
1. Server Won’t Start or Crashes on Boot
Common signs: service fails to start, unexpected reboots, crash logs during initialization.
Quick checks
- Check system resources (CPU, memory, disk space). Low disk space or exhausted memory commonly prevent services from starting.
- Inspect logs: system logs (/var/log/syslog, /var/log/messages), iScan Server logs (path depends on installation), and the kernel log (dmesg) for errors.
- Verify dependencies: database (if external), Java runtime or other required runtimes, and required OS packages.
Quick fixes
- Free disk space: delete old logs, rotate logs, or expand volume.
- Restart dependent services: database (Postgres/MySQL), message brokers, or runtime environments.
- Reinstall/repair corrupted binaries: verify file integrity and reinstall the iScan Server package if files are missing.
- Boot in recovery mode and run filesystem checks (fsck) if disk errors appear.
Prevention
- Configure log rotation and monitoring for disk usage.
- Add resource alerts and enforce minimum resource requirements.
2. Web UI Not Loading or Slow Response
Common signs: web interface times out, pages load partially, sluggish UI interactions.
Quick checks
- Confirm the iScan Server service is running and listening on the expected port (use netstat/ss).
- Test connectivity from client to server (ping, traceroute).
- Inspect web server and application logs for ⁄502 errors or timeouts.
- Check database responsiveness and query latency.
Quick fixes
- Restart web/application service: sudo systemctl restart iscan-server (or specific service name).
- Clear application cache and browser cache; try an incognito window.
- Increase application worker threads or connections if under heavy load.
- Optimize slow database queries and ensure proper indexing.
- If behind a reverse proxy or load balancer, verify proxy timeouts and buffer sizes.
Prevention
- Set up load testing and performance monitoring.
- Implement caching (CDN, reverse proxy) and scale horizontally when needed.
3. Agents/Scanners Not Reporting to Server
Common signs: endpoints don’t appear in inventory, scan results outdated, “last seen” timestamps stale.
Quick checks
- Confirm agent service is running on endpoints.
- Verify network connectivity and firewall rules (ports used by agent-server communication).
- Check agent logs for authentication or handshake errors.
- Ensure server certificate and agent trust store are valid and not expired.
Quick fixes
- Restart the agent on the endpoint.
- Re-run agent provisioning or re-enroll the agent if authentication tokens have expired.
- Open required ports on the network/firewall; verify NAT/port forwarding rules.
- Replace or renew expired TLS certificates and update the agent trust store.
Prevention
- Configure agent auto-reconnect and exponential backoff.
- Monitor agent “heartbeat” and set alerts for missed check-ins.
4. Authentication and Permission Errors
Common signs: users can’t log in, permission-denied messages, role changes not applied.
Quick checks
- Check authentication backend (local DB, LDAP/AD, SSO) status and connectivity.
- Validate time synchronization (Kerberos/SSO authentication often fails if clocks differ).
- Inspect auth logs for failed login attempts and error codes.
Quick fixes
- Restart authentication services and re-sync with LDAP/AD.
- Correct system time with NTP/chrony on server and auth systems.
- Reset problematic user account or reassign roles.
- Verify OAuth/SSO client secrets and redirect URIs if single sign-on is used.
Prevention
- Implement multi-factor authentication and account lockout policies.
- Regularly test and monitor external auth integrations.
5. Database Connection and Performance Problems
Common signs: timeouts, slow queries, errors like “connection refused” or “too many connections.”
Quick checks
- Confirm database process is running and listening.
- Monitor active connections and slow query logs.
- Review disk I/O, CPU, and memory on the database host.
Quick fixes
- Increase max connections or connection pool size in both DB and iScan application settings, but only after ensuring sufficient resources.
- Kill hung queries and restart the DB if necessary.
- Archive/prune large tables and enable proper indexing.
- Move DB to faster storage (SSD) or scale vertically/horizontally.
Prevention
- Configure connection pooling, query caching, and routine maintenance (VACUUM, ANALYZE).
- Use read replicas for reporting to reduce load on primary DB.
6. Scan Jobs Failing or Producing Incomplete Results
Common signs: scans stop mid-run, missing assets in reports, inaccurate findings.
Quick checks
- Review scan job logs for timeout, permission, or protocol errors.
- Verify credentials used by scanners (SSH, SMB, SNMP, API keys) are valid.
- Ensure network paths to scanned resources are reachable and not blocked by firewalls or ACLs.
Quick fixes
- Increase scan timeouts or adjust concurrency to reduce load.
- Update/re-enter credentials and test access manually.
- Segment scans to smaller targets or adjust scanning windows to off-peak hours.
- Repair or redeploy scanner appliances/agents with fresh configs.
Prevention
- Rotate and validate scanning credentials regularly.
- Maintain a scanned asset inventory and exclude unreachable hosts from schedules.
7. Licensing and Activation Issues
Common signs: warnings about license expiry, features disabled, or activation failures.
Quick checks
- Verify license key validity and expiry date.
- Check communication to licensing server if activation requires external validation.
- Inspect local license files and permissions.
Quick fixes
- Apply a renewed license key or re-activate using the admin console.
- If offline activation is required, follow vendor offline activation steps.
- Restart the server after applying license changes.
Prevention
- Monitor license expiry and set renewal reminders well ahead of time.
- Maintain a license management inventory.
8. Log Flooding and Disk Consumption
Common signs: disks filling fast, many repetitive log entries, system slowdown.
Quick checks
- Identify noisy components generating excessive logs.
- Check log rotation settings and retention policies.
Quick fixes
- Adjust log levels (INFO → WARN) for noisy modules.
- Enable or configure log rotation (logrotate) and compress old logs.
- Move logs to a centralized logging system (ELK/Graylog) and set retention.
Prevention
- Establish sensible logging levels and monitor log volume trends.
9. Alerts and Notifications Not Sending
Common signs: no emails/SMS/Slack messages when alerts trigger, or delayed notifications.
Quick checks
- Test notification channel configurations and credentials (SMTP server, API keys).
- Check queue/backlog in notification subsystem.
- Inspect delivery logs for bounce/backoff messages.
Quick fixes
- Reconfigure or re-authenticate SMTP/API credentials.
- Clear notification queue and restart notification service.
- Use alternative test channels to confirm system can send outbound messages.
Prevention
- Set up multiple notification channels and escalation paths.
- Monitor delivery success metrics.
10. Unexpected High CPU or Memory Usage
Common signs: server overloaded, processes consuming excessive resources, degraded performance.
Quick checks
- Use top/htop and ps to identify offending processes.
- Check recent configuration changes, heavy scan schedules, or large imports/exports.
Quick fixes
- Restart or throttle the resource-hungry service.
- Temporarily scale up CPU/RAM or move services to another host.
- Tune JVM/GC settings if iScan runs on Java (increase heap, tune GC).
Prevention
- Capacity planning, autoscaling, and process resource limits (cgroups, systemd).
- Schedule heavy tasks during off-peak windows.
Diagnostic Troubleshooting Workflow (Quick)
- Reproduce the issue or collect exact error messages.
- Gather logs (application, system, database) and relevant timestamps.
- Check resource metrics (CPU, memory, disk I/O, network).
- Isolate: disable nonessential integrations, test with minimal configuration.
- Apply incremental fixes and annotate changes for rollback.
- Escalate to vendor support with collected artifacts if unresolved.
Useful Commands and Checks
- Check service status:
sudo systemctl status iscan-server - Check listening ports:
ss -tulwn | grep :<port> - View recent logs:
journalctl -u iscan-server -n 200 - Disk usage:
df -h - Tail logs:
tail -f /var/log/iscan/iscan.log
When to Contact Vendor Support
- Repeated crashes with no clear cause after basic fixes.
- Possible data corruption in the iScan database.
- License/activation failures that affect production functionality.
- Security incidents or suspected compromise.
Provide support these artifacts: application logs, system logs, DB dumps (if requested and safe), exact timestamps, and steps to reproduce.
Final Tips
- Keep backups of configuration and the database before making major changes.
- Automate monitoring and alerting for core metrics.
- Maintain a runbook with common fixes and escalation contacts.
If you want, I can convert this into a printable runbook, a step-by-step checklist for your team, or tailored troubleshooting commands for your server OS—tell me which OS and installation type you use.
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