Failed my first attempt with a 68% back in March and honestly didn't know where I was going wrong. I was spending about 2 hours a day on subnetting drills but completely ignoring the wildcard mask logic that shows up constantly on the real exam. Second time around I gave myself 6 weeks and restructured everything.
The thing that made the biggest difference was practicing with real router configs instead of just reading theory. I grabbed a bunch of extended vs standard ACL scenarios and worked through them until I could write them from scratch without looking anything up. That took maybe 3 weeks to feel solid.
I also used an ACL practice test pretty heavily the final two weeks — scoring around 78-82% consistently before the real thing. Ended up getting an 84% on the actual exam which felt great after that first failure.
If you're in the same boat, focus on the order of operations for ACL processing and the implicit deny at the end. That trips up a lot of people who think they understand it but don't fully internalize it until they've debugged a few broken configs.
Did you use any Packet Tracer labs or just written practice? I'm finding the hands-on simulation questions the hardest part. Reading about ACLs is easy but configuring them under time pressure is a different thing entirely.
The wildcard mask thing got me too on my first pass. I spent like 10 hours just on that one concept before it finally made sense. Once you see it as the inverse of a subnet mask it clicks fast.
Congrats on the 84%. The jump from failed to passed feels huge. I'm three weeks into my prep and the implicit deny rule is exactly where I keep tripping myself up — good to know that's a real exam focus area.
Six weeks sounds about right for a solid prep cycle. I did 5 weeks the first time and rushed the last week, which showed on test day — barely scraped through at 74%. Next exam I'm building in a full buffer week at the end just for review.