reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /v DefaultTTL /t REG_DWORD /d 65 /f

The standard TTL unit (Model: OptiTemp X-4) is a deceptively simple beast:

Yeraldin Gonzalez’s TTL install guide is (verification and rollback). With a few minor additions—IPv6 notes, a brief TTL primer, distro‑specific persistence, and a mention of nftables —the tutorial would become a complete reference for anyone who needs to enforce a custom TTL value on Linux routers.

Yeraldin Gonzalez discovered and shared a trick: This effectively hides your tethering activity.