x.y.z.0 ip address

[hs08]

Hello,

If i have subnet 10.10.10.0/23 this mean :

• Network Addr is 10.10.10.0
• Broadcast Addr is 10.10.11.255
• Usable IP range from 10.10.10.1 - 10.10.11.254

My question is IP 10.10.11.0 is valid address?

[MHM Cisco World · Accepted solution]

since 10.10.11.0 is not network and not broadcast of 10.10.10.0/23 then you can use it 
MHM

[hs08]

Thanks for your confirmation. But are you ever use .0 as host ip address?

[MHM Cisco World]

sure the mask /23 allow you to use .0

MHM

[Leo Laohoo]

Command:  ip subnet-zero

[paul driver]

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@hs08 wrote:

Hello,

If i have subnet 10.10.10.0/23 this mean :

• Network Addr is 10.10.10.0
• Broadcast Addr is 10.10.11.255
• Usable IP range from 10.10.10.1 - 10.10.11.254

My question is IP 10.10.11.0 is valid address?

---

yes....

[Joseph W. Doherty]

"My question is IP 10.10.11.0 is valid address?"

As 10.10.11.0/23, as others have already noted, yes it is a valid "normal" IP address.

To be clear, it's easy to believe x.x.x.0 is "special", because of historic class C network address block allocations, but the real issue is the first IP within a network is also used as network address, which is confusing, but actually doesn't preclude using an IP like 10.10.11.0/24 as a host IP, but also historically, sometimes the first network IP was used as a network broadcast IP.  So, we generally exclude using the first network block IP, the network address, except in the case of using a /31 or /32.