This guide shows you how to automatically reconfigure your router after a factory reset using Dynamic DNS (DDNS) and a script that runs on startup. This means you don\u2019t have to manually update settings every time.<\/p>\n
Understand the Problem<\/strong><\/p>\n When a router resets, it loses its configuration, including your port forwarding rules and any custom DNS settings. This guide automates restoring those settings.<\/p>\n Choose a Dynamic DNS (DDNS) Provider<\/strong><\/p>\n DDNS services give you a consistent domain name even if your IP address changes. Popular options include No-IP, DynDNS, and DuckDNS. For this example, we\u2019ll assume you\u2019ve chosen DuckDNS as it\u2019s free.<\/p>\n Create an account on DuckDNS<\/a>. Configure Your Router for DDNS<\/strong><\/p>\n Most routers have built-in DDNS support. The exact steps vary by router model, but generally:<\/p>\n Log in to your router\u2019s web interface (usually 192.168.1.1 or 192.168.0.1). Create a Configuration Script<\/strong><\/p>\n This script will run after each reboot to restore your desired settings.<\/p>\n The script language depends on your router\u2019s firmware. Many routers support shell scripts (.sh) or Lua. We\u2019ll use a shell script for this example. #!\/bin\/sh<\/p>\n # Your DuckDNS token and domain name # Get the current public IP address # Update DuckDNS record # Restore port forwarding rules (example for port 80 to internal IP 192.168.1.10) # Restore custom DNS settings (example using nsupdate, requires configuration in \/etc\/nsupdate.conf) echo “Router config updated successfully!”<\/p>\n Important:<\/strong> The pfctl command is specific to OpenBSD-based routers (like some ASUS models). Adjust this part of the script based on your router\u2019s firewall configuration.<\/p>\n Configure Router Startup Script Execution<\/strong><\/p>\n This step tells your router to run the router_config.sh script automatically after each reboot.<\/p>\n Again, this varies by router model. Look for a section in the web interface called \u201cStartup Scripts\u201d, \u201cCustom Commands\u201d, or similar. \/path\/to\/router_config.sh<\/p>\n Replace \/path\/to\/router_config.sh with the actual location of your script on the router\u2019s filesystem.<\/p>\n Test Your Configuration<\/strong><\/p>\n Reboot your router. Script Permissions:<\/strong> Ensure the script has execute permissions. You might need to use SSH to connect to your router and run chmod +x \/path\/to\/router_config.sh. The post Router Auto-Config After Reset<\/a> appeared first on Blog | G5 Cyber Security<\/a>.<\/p>","protected":false},"excerpt":{"rendered":" TL;DR This guide shows you how to automatically reconfigure your router after a factory reset using Dynamic DNS (DDNS) and a script that runs on startup. This means you don\u2019t have to manually update settings every time. Steps Understand the Problem When a router resets, it loses its configuration, including your port forwarding rules and […]<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-6396","post","type-post","status-publish","format-standard","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/cybersecurityinfocus.com\/index.php?rest_route=\/wp\/v2\/posts\/6396"}],"collection":[{"href":"https:\/\/cybersecurityinfocus.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cybersecurityinfocus.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/cybersecurityinfocus.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6396"}],"version-history":[{"count":0,"href":"https:\/\/cybersecurityinfocus.com\/index.php?rest_route=\/wp\/v2\/posts\/6396\/revisions"}],"wp:attachment":[{"href":"https:\/\/cybersecurityinfocus.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6396"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cybersecurityinfocus.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6396"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cybersecurityinfocus.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6396"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nAdd a domain name (e.g., myrouter.duckdns.org).
\nNote your token and domain name \u2013 you\u2019ll need these later.<\/p>\n
\nFind the DDNS settings section (often under Advanced Settings, WAN, or Dynamic DNS).
\nEnter your DuckDNS domain name and token.
\nSave the changes. Your router should now automatically update its IP address with DuckDNS.<\/p>\n
\nCreate a file named router_config.sh with the following content, replacing placeholders with your actual values:<\/p>\n
\nTOKEN=”YOUR_DUCKDNS_TOKEN”
\nDOMAIN=”myrouter.duckdns.org”<\/p>\n
\nIP=$(curl -s https:\/\/api.ipify.org)<\/p>\n
\ncurl -s “https:\/\/www.duckdns.org\/update?domains=$DOMAIN&token=$TOKEN&ip=$IP” > \/dev\/null<\/p>\n
\npfctl -a “rdr pass on eth0 proto tcp from any to any port 80 -> 192.168.1.10 port 80” <\/p>\n
\n# nsupdate -f \/etc\/nsupdate.conf<\/p>\n
\nAdd the following command:<\/p>\n
\nCheck that your DDNS record is updated correctly on DuckDNS (or your chosen provider).
\nVerify that port forwarding rules are working as expected.
\nIf there are errors, check the script\u2019s output (if available) or examine the router\u2019s system logs for clues.<\/p>\nTroubleshooting<\/h2>\n
\nFirewall Rules:<\/strong> Double-check that your firewall rules allow outbound connections for DDNS updates (usually port 80 or 443).
\nScript Errors:<\/strong> Carefully review the script for typos and incorrect commands. Use SSH to connect to the router and run the script manually to see any error messages.<\/p>\n