Confusing example in Network+ Passport study guide

akuj1n

I have been doing my second round of studying for the network+ exam, this time with the network+ passport written by Mike Meyers (yeah baby!) In the section on subnetting and cidr addressing he gives a very confusing example, where the subnetting makes sense but my question comes after the network is segmented.

In his example he uses

192.168.4.0/26 to create 4 subnets (in this example to segment off public wifi from back office network resources etc.)

my question is after this.

In this example 192.168.4.0/26 wouldnt that mask out the default gateway (lets say 192.168.4.1) for the 3 subsequent subnets?

would you need an individual gateway for each subnet, or one firewall with remapped internal lan ports, one port mapped to an ip on each subnet?

It seems like in this example only one subnet would have routed external access, he doesnt actually explain what happens after you segment the network to make it actually function how he is representing in his example.

the subsequent networks being
192.168.4.0/26
192.168.4.64/26
192.168.4.128/26
192.168.4.192/26

Rosco2382

It appears you are missing one octet.

akuj1n

its shorthand..... 192.168.4.0/26 can be shortened to 192.168.4/26 its common sense in this field that 4 octets are needed.

think of it as shorthand for ipv6 ::1 for loop back instead of :0:0:0:0:0:0 etc

Rosco2382

Sorry I'm just starting my Network+ and understanding of subnetting.

akuj1n

no worries, just fyi

SharkDiver

Yes, Sir.
Every subnet will need it's own default gateway.

akuj1n

THANKS!, I don't know why its not explained in the book when its the next logical step in getting the scenario going, he stop at just the segmentation and confused the living $hit out of me.

Im guessing on a nice firewall you could just remap lan ports and have them mapped one for each subnet.

johns2025

Be sure to read Subnetting Made Easy, a post on this site. It is super well written and much more useable than Mike's section on subnetting.