This is a short story I read during the late 1980s, probably in an anthology book.
Earth has been invaded by aliens, who have proven to be unstoppable - governments and countries are rapidly conquered and only a guerrilla style resistance force is left.
The aliens landed in one place, and they established a base around their landing site - its described as similar to spokes and wheels, radiating out from the landing site.
The landing site was bombed with a nuclear weapon early on, but the aliens were using an impenetrable force field and as such their base was untouched.
The aliens use tripod-style (could have had more legs) walkers to move around the country side and fight the resistance with. These walkers could be destroyed by resistance fighters.
After many failed plans, the protagonist resistance fighter group takes down an alien walker in an ambush, and get inside it - one of the group takes a glowing ball about the size of a football from the alien walker.
Shortly afterward, the resistance group find themselves at the edge of the force field surrounding the now massive alien base - they still cannot find a way through.
In frustration, the group member carrying the glowing ball throws it at the force field, and it passes right through.
The group gather more glowing balls from other walkers, and pass through the force field.
Inside the base, they are quickly rumbled, and have to fight their way out - during this fight, they find themselves in a room with some aliens, whom they ultimately kill in a frenzied battle. They then discover all the aliens and alien walkers in the base have stopped moving, toppled over etc.
They exit the base, to find hundreds of thousands of alien walkers around the base, as if returning to it in a hurry to defend against the intruders. All of these alien walkers were motionless and essentially dead.
The team had killed the leadership and as some sort of hive mind or centrally controlled force, the rest of the alien invasion force had simply ceased to function.
Earth was saved.
This short story may have been part of an anthology, one other story of which I have posted another question about.
I can completely rule out any version of the War of the Worlds, and any book related to the Tripods.
