Introduction
Network logging is essential for tracking system events, detecting security incidents, and troubleshooting network issues. However, misconfigured logging settings or log collection failures can lead to missing logs, incomplete event tracking, or excessive storage consumption.
This guide will help you identify and fix network logging issues, ensuring that logs are correctly generated, stored, and analyzed.
What Causes Network Logging Issues?
Several factors can lead to logging failures, including:
✅ Incorrect Log Configuration – Devices not sending logs to the central log server.
✅ Firewall or Security Rules Blocking Syslog Traffic – Preventing log collection.
✅ Log Overload or Storage Issues – Large log files causing performance degradation.
✅ Time Synchronization Issues – Inconsistent timestamps due to NTP misconfiguration.
✅ Syslog, Event Log, or Logging Agent Not Running – Services failing to collect logs.
✅ Permissions or Access Control Issues – Preventing log files from being written.
Now, let’s go through step-by-step troubleshooting to resolve logging issues.
Step 1: Verify Logging Services Are Running
If logs are not being collected, check if the logging service is active.
🔹 Check Syslog Status (Linux):
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sudo systemctl status rsyslog
🔹 Restart Syslog Service (Linux):
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sudo systemctl restart rsyslog
🔹 Check Windows Event Log Service:
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Get-Service | Where-Object { $_.Name -like “*EventLog*” }
🔹 Restart Windows Event Log Service:
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net stop EventLog
net start EventLog
If logging services are running but logs are missing, move to Step 2.
Step 2: Verify Syslog and Event Log Configuration
Check if devices are configured to send logs to the correct location.
🔹 Check Syslog Configuration on Linux:
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cat /etc/rsyslog.conf
🔹 Ensure Syslog Forwarding is Configured (Linux Example):
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*.* @192.168.1.100:514
🔹 Check Windows Event Log Settings:
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wevtutil gl Application
🔹 Ensure Logs Are Being Forwarded (Windows Example):
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wevtutil sl Application /rs:192.168.1.100
If configurations look correct but logs are not arriving, proceed to Step 3.
Step 3: Check Firewall Rules Blocking Log Traffic
Syslog and other logging services use specific ports (514 for Syslog, 6514 for Secure Syslog, 5985 for Windows Event Forwarding), which may be blocked.
🔹 Check Firewall Rules on Linux:
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sudo iptables -L | grep 514
🔹 Check Windows Firewall Rules:
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netsh advfirewall show allprofiles state
🔹 Allow Syslog Traffic (Linux Example):
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sudo iptables -A INPUT -p udp –dport 514 -j ACCEPT
🔹 Allow Syslog Traffic on Windows Firewall:
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netsh advfirewall firewall add rule name=”Syslog” protocol=UDP dir=in localport=514 action=allow
If firewall rules are correct but logs are still missing, move to Step 4.
Step 4: Check Log File Storage and Rotation Settings
If logs are not appearing or being deleted too quickly, storage or log rotation settings may be misconfigured.
🔹 Check Disk Space Usage:
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df -h
🔹 Check Log Rotation Settings (Linux):
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cat /etc/logrotate.conf
🔹 Ensure Logs Are Not Rotating Too Frequently:
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/var/log/syslog {
weekly
rotate 4
compress
missingok
notifempty
}
🔹 Manually Trigger Log Rotation for Testing:
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sudo logrotate -f /etc/logrotate.conf
If log storage looks fine but logs are missing or outdated, proceed to Step 5.
Step 5: Ensure Log Timestamps Are Correct (NTP Configuration)
Incorrect timestamps can misalign logs, making event analysis difficult.
🔹 Check System Time on Linux:
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timedatectl status
🔹 Check NTP Sync Status:
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ntpq -p
🔹 Synchronize System Time:
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sudo timedatectl set-ntp on
🔹 Force Manual Time Sync (Linux):
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sudo ntpdate -u pool.ntp.org
🔹 Check Windows NTP Configuration:
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w32tm /query /status
If timestamps are correct but logs are still missing, proceed to Step 6.
Step 6: Test Log Collection and Forwarding
If logs are still missing, test whether they are being sent and received correctly.
🔹 Send a Test Syslog Message (Linux):
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logger -p local0.info “Test message”
🔹 Manually Query the Windows Event Log for Specific Errors:
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wevtutil qe System /c:10 /rd:true /f:text
🔹 Check Logs on the Central Logging Server:
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tail -f /var/log/syslog
If test messages do not appear in the logs, move to Step 7.
Step 7: Update Logging Software and Agents
Outdated software may cause incomplete logging or compatibility issues.
🔹 Check Rsyslog Version on Linux:
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rsyslogd -v
🔹 Update Rsyslog on Linux:
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sudo apt update && sudo apt upgrade rsyslog -y
🔹 Check and Update Windows Logging Components:
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wmic qfe list brief /format:table
🔹 Update Windows Event Forwarding Services:
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wecutil ss /update
If logs still do not appear or are incorrect, move to Step 8.
Step 8: Monitor Logging Performance and Optimize Settings
If logs are delayed or incomplete, monitor log processing performance.
🔹 Monitor Rsyslog Performance (Linux):
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rsyslogd -N1
🔹 Check Log Collection Speed with Log Analysis Tools:
- Wireshark: Monitor syslog traffic (port 514).
- Graylog/Splunk/ELK: Track log ingestion rates.
🔹 Optimize Log Processing Speed by Adjusting Buffering Settings:
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$MainMsgQueueSize 50000
If logs are now properly collected and stored, your issue is resolved! 🎉
Best Practices to Prevent Future Logging Issues
✅ Enable redundant log storage to prevent data loss.
✅ Use structured logging formats (JSON, CSV) for easier analysis.
✅ Rotate and archive logs to prevent excessive disk usage.
✅ Monitor log collection in real-time to detect failures early.
✅ Use centralized logging solutions (ELK, Splunk, Graylog) for better analysis.
Get Expert IT Support for Network Logging and Log Analysis
Still facing network logging failures, missing logs, or log analysis issues?
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