I put mine on the front bumper using 4X4RAKS, which are commonly available. These are sheetmetal brackets that can be bolted to any flat surface. They're also lockable, though by necessity the padlock has to be small.
Yes, being placed on the face of the front bumper runs the risk of impact damage. So far I've been fortunate. I put it there as an expedient. On top of the bumper are lights that the jack would block the beam of, and my intention is to install a winch, whose plate would be on top of the bumper. As is the case with most expedients, I haven't gotten around to a permanent fix.
Also note that if you have your Hi Lift externally mounted, you should clean the mechanism on a regular basis and lube it. It will ingest a lot of dirt that can gum it up to the point of sticking or even jamming. The lower it is mounted, the worse this is.
Hi Lift sells the 4X4 RAK. Also note the Handle Keeper, which is a good for some mounting positions.
Hi-Lift Accessories - Handle Keeper, Lift-Mate, Off-Road Base, Off-Road Kit, 4XRAC, LOC-RAC, Bumper Lift, Jack Protector, Fix-It Kit | Hi Lift Jack Company
Be sure to check out this thread too:
https://forum.ih8mud.com/40-55-series-tech/158569-best-place-attach-hi-lift-jack.html
And this one too:
https://forum.ih8mud.com/chit-chat-...p-clamp-down-there-shovels-axes-hi-lifts.html