Subnet mask

OK, This is probably the most bone-headed question ever asked on this forum, but I am confused by it, and that's what forums are all about after all.

Anyway, according to the dude on the video on my online course a class A private network would have an ip address starting with 10.x.x.x with a subnet mask of 255.0.0.0, class B 172.68.x.x - 255.255.0.0, class C 192.168.x.x - 255.255.255.0

Why is my ip address 10.11.whatever and subnet mask is 255.255.255.0?

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Comments

Trifidw

This is covered within the CCNA and there are loads of examples of subnetting in the CCNA forum.

You have an IP address, this is part of a network 10.0.0.0/8 (255.0.0.0). This was then subneted down to a /24 so the mask will be 255.255.255.0. You can also go 'up' too so have a 192.168.0.0 255.255.0.0 At the moment he is only talking about classful networks that have not been subneted.

EdTheLad

Class A 1-126
Class B 128-191
Class C 192 - 223
This should have really been asked in the ccna forum. Class A /8 , Class B /16 and Class C /24.They are called the major network boundaries. If you have an address 10.11.1.0 255.255.255.0, this is essentially a class A address with 16 bits of subnetting. These classes were important in the past
with classful routing, classful table lookups and supernetting limitations on routing protcols.
I can't really think of where you would hit an issue with this today, other than using rip and trying to supernet, but i wouldn't think there are too many rip networks out there.