Tech Musings

May 28, 2026 · Operations

EdgeRouter X PPPoE IPv6 Stalls: MTU 1492 vs Router Advertisement Prefix Overwrite Trap

Enabling IPv6 on an EdgeRouter X PPPoE link caused intermittent SSL time‑outs because the PPPoE MTU of 1492 conflicted with the client’s default MTU, and the router‑advertised link‑mtu overwrote the DHCPv6‑PD‑generated SLAAC prefix, stripping internal devices of a global IPv6 address; manually configuring both MTU and prefix resolved the issue.