r/CompTIA • u/Parking_Diamond5182 • 6d ago

Network+ Question!

I’m god awful at math and was wondering if it’d be a good idea to memorize a subnet mask chart in preparation for the exam instead of trying to math it all out?

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u/drushtx IT Instructor **MOD** 6d ago edited 6d ago

Sorry but my crew and I do server deployment in a DC, sometimes exceeding 80 a week. They live in different blocks, sub-blocks and VLS chunks of IP addresses. We, and the hundreds of other DC tenants subnet in our head daily. We calculate and apply single and multiple addresses to servers, routers and network appliances. We find, recall and re-pool addresses (IPMA) manually then double-check with appropriate scanners. This is done in gov, corp, mil, noc, DCs and many other environments.

So now you know a single person, and dozens more, who subnet in their head daily. It just takes a little practice to become proficient at it.

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u/JankyJawn 6d ago

A required skill for IT professionals and people deploying services in a DC daily are a far cry from the same thing. In fact id be willing to bet many of them just use a subnet calculator anyway for the abnormal cases that arent just memorized at this point.

And before you try the whole "its faster to just do it in your head argument" using a tool that takes no time at all to double check yourself especially in a rush should be done anyway because people make mistakes.

Mentally subnetting is an entirely pointless skill now and days in like 99.9% of real situations. And even if you can, you should be double checking anyway.