• Name: EPiGEN Crystal (official) | 자몽 (korean)

• Model: Raspberry Pi 2 Model B+ Raspbierry Pi Model B
• : 1T mount on ~/Storage - Storage in details
• : Wireless (wlan0) & Wired (eth0) - Júne's home network
• Private storage and Backup point

• fresh installation _{— Updated on 2018/02/25 01:13}

• Change Boot microSD memory due to physical defects

Raspbian (debian) server can be used as a machine recording log from external devices such as router.
Install syslog-ng and related mods as well.

  sudo apt-get install syslog-ng 

After finishing installation, edit /etc/syslog-ng/syslog-ng.conf.

  source s_net { udp(ip(0.0.0.0) port(514)); };  
 
  destination d_router { file(“/var/log/router.log”); }; 
 
  log { source(s_net); destination(d_router); }; 

source s_net defines the source where records are from 0.0.0.0 will be bind to all interfaces.
destination set your arbitrary name like d_router and set the path of log file.
log tells what source to use and what destination to take. If you have 'filter' option to utilize for more refined log results.
Create log file.

  sudo touch /var/log/router.log 

And restart syslog-ng service

  sudo systemctl stop syslog-ng.service 
  sudo systemctl start syslog-ng.service 

For sensitive reason, you would better to stop & start service instead of restart.
Check size of log file is getting bigger and contents of log file.

For archiving and compressing log files, edit /etc/logrotate.d/syslog.ng

/var/log/router.log
{
        rotate 4
        weekly
        missingok
        notifempty
        compress
        delaycompress
        sharedscripts
        postrotate
                invoke-rc.d syslog-ng reload > /dev/null
        endscript
}