System Logging

When troubleshooting problems with your firewall, it is very likely you have to check the logs available on your system. In the UI of OPNsense, the log files are generally grouped with the settings of the component they belong to. The log files can be found here:


System Log System ‣ Log Files ‣ General Most of all system related events go here
Backend / config daemon System ‣ Log Files ‣ Backend Here you can find logs for config generation of API usage
Web GUI System ‣ Log Files ‣ Web GUI Lighttpd, the webserver of OPNsense itself, logs here
Firmware System ‣ Firmware ‣ Log File Updates from the packaging system go here
Gateways System ‣ Gateways ‣ Log File Lists Dpinger gateway tracking related log messages
Routing System ‣ Routes ‣ Log File Routing changes or interface events


Log files on file system: /var/log/system.log (clog) /var/log/configd.log (clog) /var/log/lighttpd.log (clog) /var/log/pkg.log (clog) /var/log/gateways.log (clog) Note: By default gateway monitoring is disabled, so the log will be empty. /var/log/routing.log (clog)


Wireless Interfaces ‣ Wireless ‣ Log File When using wireless features of OPNsense you find the logs here
Point-to-Point Interfaces ‣ Point-to-Point ‣ Log File PPP dialup logs like PPPoE are found here


Log files on file system: /var/log/wireless.log (clog) /var/log/ppps.log (clog)


Live View Firewall ‣ Log Files ‣ Live View View firewall logs in realtime, smart filtering can be applied
Plain View Firewall ‣ Log Files ‣ Plain View Just the plain contents how **pf* logs into filter.log *


Log files on file system: /var/log/filter.log (clog)

Live View

Live view updates itself in realtime if a rule is matched that has logging enabled or one of the global logging options is enabled under: System ‣ Settings ‣ Logging

For better troubleshooting you can provide a filter string. This filter may include regular expressions. Lets assume one logging entry as one single string without special separators.

So for just displaying packets that match DNS replies from wan to your lan clients in segment, you have to use:


or to be even more correct

WAN .* :53 .* 192.168.1.
Interface 1 or more characters first match of port 1 or more characters destination ip address


IPsec Log VPN ‣ IPsec ‣ Log File Everything around IPsec goes here
OpenVPN Log VPN ‣ OpenVPN ‣ Log File OpenVPN logs everything here


Log files on file system: /var/log/ipsec.log (clog) /var/log/openvpn.log (clog)


Captive Portal Services ‣ Captive Portal ‣ Log File Events from Captive Portal go here
DHCPv4 Services ‣ DHCPv4 ‣ Log File DHCP events get logged here
Dnsmasq DNS Services ‣ Dnsmasq DNS ‣ Log File The DNSmasq Forwarder logs
HAProxy Services ‣ HAProxy ‣ Log File The logs of the Reverse Proxy
Intrusion Detection Services ‣ Intrusion Detection ‣ Log File Suricata Logs are here
Network Time Services ‣ Network Time ‣ Log File NTP daemon logs
Unbound DNS Services ‣ Unbound DNS ‣ Log File Unbound resolver logs can be found here
Web Proxy Services ‣ Web Proxy ‣ Log File Squid access.log, store.log and cache.log


Log files on file system: /var/log/portalauth.log (clog) /var/log/dhcpd.log (clog) /var/log/dnsmasq.log (clog) /var/log/haproxy.log (clog) /var/log/ntpd.log (clog) /var/log/suricata.log (clog) /var/log/resolver.log (clog) /var/log/squid/access.log (text) /var/log/squid/cache.log (text) /var/log/squid/store.log (text)

Circular Logs

Most of the core features log to circular log files so they will not grow bigger than a predefined size. You can tune this value via System ‣ Settings ‣ Logging. There, you can also disable the writing of logs to disk or reset them all.

You can view the contents via CLI with:

clog /path/to/log

or follow the contents via:

clog -f /path/to/log

Plugin Logs

Many plugins have their own logs. In the UI, they are grouped with the settings of that plugin. They mostly log to /var/log/ in text format, so you can view or follow them with tail.

Log Settings

Log settings can be found at System ‣ Settings ‣ Logging. The settings are in two groups, one for local logging and one for remote logging.

An overview of the local settings:

Setting Explanation
Reverse Display When enabled, the most recent log entry will be displayed on top.
GUI Log Entries to Display Number of log entries displayed in the GUI.
Log File Size (Bytes) Maximum size of circular logs (which most OPNsense log files are)
Log Firewall Default Blocks Turning these off means that only hits for your custom rules will be logged.
Web Server Log If checked, lighttpd errors are displayed in the main system log.
Disable writing log files to the local disk Useful to avoid wearing out flash memory (if used). Remote logging can be used to save the logs instead if desired.
Reset Logs Clear all logs. Note that this will also restart the DHCP server, so make sure any DHCP settings are saved first.

An overview of the remote settings:

Setting Explanation
Enable Remote Logging Master on/off switch
Source Address Which interface to bind to. Select “any” if you want to use a mix of IPv4 and IPv6 servers.
IP Protocol Preferred IP version (it will this first). Will only be used if “Source Address” is not an IP.
Remote Syslog Servers IP addresses of remote syslog servers, or IP:port combinations.
Remote Syslog Contents Can be used to selectively log event categories