Subnet mask

bigeuan

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?

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.