Cisco switch: Interface Vlan 1 disregards subnet?

zeratulzeratul Member Posts: 7 ■□□□□□□□□□
in CCNA & CCENT
Hi wonderful people of TE,

I experimented a while back setting up different subnets for my Interface vlan 1 on Cisco switches. On Switch-1, I set the IP to 10.0.0.1/24; Switch-2 to 10.0.0.2/16. Why is it that I can ping each other (not using any L3 device) knowing they are in different subnets? Isn't this violate subnet restriction?

Can somebody educate me with this?

Thanks!
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Comments

  • altdrugzaltdrugz Member Posts: 69 ■■□□□□□□□□
    Without being accurate or explaining the true reason behind this, this happens because the /16 boundary "includes" the /24 (thats why they are called overlapping subnets). If you set up for example in 2 routers their serial interfaces with 10.0.0.1 /28 and 10.0.0.2 /29 respectively you will be able to ping them but if you change the second ip to 10.0.0.17 /28 you will not be able to do so because they are belonging to "totally" different subnets.
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  • Mrock4Mrock4 Banned Posts: 2,359 ■■■■■■■■□□
    The reason it works is that 10.0.0.1 and 10.0.0.2 both exist in each subnet (as altdrugz said, they overlap), so each device THINKS the other device is in the same subnet, and fires off replies.
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