What does an IP ending in 0 signify?

Posted on 2006-04-26
Last Modified: 2013-11-16
When I tried to tell a norton firewall to allow traffic from the local network range, from thru, it said, "IP already allowed".

I looked on the "allowed List".  The firewall's "network wizard" had already allowed this:

What does this mean? I don't think I've seen an IP ending in 0 before (sorry). Does the "0" signify a range from "1 thru 254"?  

If so -- does that apply in any of the 4 octets?
Question by:dgrrr
    LVL 142

    Accepted Solution

    a 0 at the end is like a wild-card, allowing all ip addresses in that range 1-254
    LVL 12

    Expert Comment

    angelIII is rite, adding to it

    it is also called as network address

    example (this address is for whole network staring from 192.168.1

    in the same way for is the network address for

    LVL 1

    Expert Comment

    "The firewall's "network wizard" had already allowed this:"

    this means that u'r firewall will allow all the address it the range to

    LVL 16

    Expert Comment

    A .0 address is meaningless without a corresponding subnet mask or CIDR notation - if your have a subnet wider than /24, an addressable host with an IP ending in .0 certainly exists.

    That being said, I agree that the .0 address likely refers to the entire corresponding /24 subnet, since firewall manufacturers love to make their devices/software interpret the IP spec as creatively as possible, and their configuration interfaces are as brain-dead as possible...  

    Regardless, it should be noted that the accepted answer is not correct for all cases.


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