Hi Joker,
I'm not entirely certain as to why System Mechanic is suggesting disabling Dead Gateway Detection is a security enhancement.
Essentially all that happens when you enable this, is that a default gateway can be switched to an alternate IP to prevent the failure of TCP data to reach its destination.
If you disable this value by modifying its Data value and changing its setting from
1 (i.e. enabled) to
0 (i.e. disabled) you are overriding a Networking feature of Windows Networking that typically only someone running a large network using their own protocols would bother doing.
In your case, you are saying System Mechanic wants you
to add this value.
I do not believe this advice is warranted.
You can read more about Dead Gateway Protection here:
https://docs.microsoft.com/en-us/previous-versions/aa454008(v=msdn.10)?redirectedfrom=MSDN
Regards,
Regedit32