Home router drops PPPoE session daily at 03:00 and reconnects with different public IP

Environment

Consumer-grade router running vendor firmware, ISP uses PPPoE with dynamic public IP and daily DHCP lease renewals; router uptime 14 days; router config contains PPPoE credentials and no custom cron jobs configured by the user.

Symptoms

Every day at 03:00 local time the internet connection drops for 1–3 minutes, internal LAN remains up, remote services report client's public IP changed after reconnect, some long-lived TCP connections (VPN, SSH) disconnect.

Observations

Router system log shows PPPoE LCP close and subsequent PAP authentication at 03:00; no obvious hardware temperature or power-cycle messages; ISP monitoring page shows PPPoE session reset from their CO at same minute on multiple days; router firmware revision is two releases behind current vendor build.

Already attempted

Rebooted router and modem, swapped Ethernet cable between modem and WAN port, restored router to factory defaults and re-entered PPPoE credentials, enabled persistent keepalive in router PPPoE settings (where available), contacted ISP who confirmed they see repeated re-auth events and an automated script run at 03:00 in their network for some customers.

Question

What reversible steps can I take to prevent daily PPPoE drops (or mitigate their impact) and how do I distinguish whether the root cause is my router firmware, ISP-side scheduled maintenance, or PPPoE session timeout settings?

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AI DIAGNOSTICS

Incident analysis

Updated 1w ago• Trouble ID

Most likely causes

ISP scheduled maintenance or automated PPPoE/ DHCP/ NAT rotation scripts that terminate sessions nightly 100%

Router firmware bug that triggers PPPoE reauthentication or fails to preserve session state during upstream maintenance 20%

Line or modem instability leading to a brief PPPoE LCP close that is handled differently across devices 10%

Summary

Daily PPPoE disconnects at a consistent time strongly point to an orchestrated event: either a scheduled ISP-side task (authentication refresh, dynamic maintenance, or carrier NAT rotation) or a device-side scheduled job (cron/maintenance on router firmware). Less likely causes include line instability causing PPPoE link flaps, or router firmware bug that triggers periodic reconnection when the router's internal timer interacts badly with PPPoE keepalive settings. The fact that the ISP sees the session resets at the same minute and multiple customers affected suggests an ISP-initiated action; however router firmware can still fail to resume seamless session handling and cause client-visible reconnects and TCP connection loss.

Suggested Fixes

Diagnostic step 1

Collect evidence: enable detailed PPPoE and system logging on the router around 02:55–03:10 for several days and export logs; capture timestamps to correlate with ISP logs.

Diagnostic step 2

Temporarily swap to a different router or run a router in passthrough mode with a spare device to see if the behavior persists (reversible and non-destructive).

Diagnostic step 3

Update router firmware to the latest stable vendor release or revert to a known-good firmware if the issue started after an update; perform after saving current config.