Touring Baghdad's ground defenses

ANBAR PROVINCE, Iraq -- Nothing in the bustle of Abu Ghraib's market hints there's a war zone just down the road.

Commander Ali Majidi wants to show CBS News how safe it is. We ask him how many armed incidents there have been since July.

"Only two IEDs," he says, "targeting the Iraqi Army."

But ISIS isn't far out of town ...

In the general's American Humvee, we cross four miles of farmland -- deserted now except for the occasional military sentry.

This is part of the security belt around Baghdad.

We are headed for its western edge --only 13 miles from Baghdad's airport.

The line of defense is an earth berm and sniper shield guarded by a battalion of Iraqi soldiers camped on the dusty plain.

ISIS fighters are just a couple of miles in the trees over my shoulder. But the front line is static -- neither side is moving forward or back. Just trading occasional fire.

But there are no guarantees. Sure enough, the Iraq army suddenly opened up.

ISIS had just fired a mortar over the berm.

The soldiers returned fire at the village of As Subhaiyat -- just visible across no-man's land. And prepared a mortar of their own ...

It's unlikely to do much damage. But the soldiers hope it will stop ISIS from advancing on them -- or the capital.

Then a third ISIS mortar whistled in -- and the mortars seemed to be getting closer and more accurate.

It was time to go.

Nobody really expects ISIS in a major military offense to push back those soldiers into Baghdad. But they are expecting ISIS to ratchet up a military offensive.