Symptoms
- Long list of blocked connection attempts in router or firewall logs
- Unfamiliar IP addresses shown as sources
- Curiosity or concern after checking logs for the first time
- No actual disruption to internet service
Likely causes
- CommonRoutine internet background scanningAutomated bots constantly scan random IP addresses across the internet looking for open ports, unrelated to you specifically.
- CommonFirewall correctly doing its jobA healthy firewall log showing blocked attempts means the protection is working as intended.
- Less commonTargeted attack attemptRepeated, sustained attempts from the same source specifically targeting your network could indicate a deliberate attempt, though this is uncommon for home networks.
What to do
- Understand that occasional blocked connection attempts in a firewall log are normal and expected, not evidence of a breach.
- Confirm the firewall or router firmware is up to date, since updates often improve blocking rules.
- Change default router admin credentials if you haven't already, to reduce the chance of the router itself being targeted.
- Make sure remote management of the router is turned off unless you specifically need it.
- If the same source IP appears with unusual frequency or a device on your network is behaving oddly, investigate further.
- Consider enabling any built-in intrusion detection or additional logging your router offers.
- No action is generally needed for ordinary background scanning alone.
When to call a pro
If you suspect a targeted attack combined with actual signs of compromise on a device, a network security professional can review the logs in depth.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.