By default, NGINX uses the predefined combined logging format
log_format combined '$remote_addr - $remote_user [$time_local] '
'"$request" $status $body_bytes_sent '
'"$http_referer" "$http_user_agent"';The default logging format is then used, also by default, to log access to the web server to </path/to/logs>/access.log
access_log logs/access.log combined;I like to use this format for reverse proxy logging
log_format combined_plus '$time_local: ($server_name) $remote_addr /// $remote_user /// "$request"->$status /// Size:$body_bytes_sent / Referer: $http_referer / Agent: $http_user_agent';I occasionally use the following log format to troubleshoot my proxy configurations
# Defined in /etc/nginx/nginx.conf
log_format debug1 'DEBUG1: $time_local / Status: $status / RemoteAddr: $remote_addr / XForwardedFor: $http_x_forwarded_for / ProxyAddXForwardedFor: $proxy_add_x_forwarded_for';
# Defined in the [server] block I'm troubleshooting
access_log /var/log/nginx/troubleshooting.log debug1;