What is CIDR?

CIDR, short for Classless Inter-Domain Routing, is a replacement for the older Classful network addressing architecture that was in use since 1981. CIDR was introduced in 1993 to address the issue of IP address shortage.

The CIDR method divides the address space for Internet Protocol Version 4 (IPv4) into five address classes. Each class, coded in the first four bits of the address, defines either a different network size, i.e. number of hosts for unicast addresses (classes A, B, C), or a multicast network (class D). The fifth class (E) address range is reserved for future or experimental purposes. Now, IPv6 is fast replacing IPv4 allowing huge expansion for more users and devices on the internet. 

To discover devices using CIDR, go to Settings -> Discovery -> CIDR and enter the Network IP and its corresponding Maskbit.

Maskbit:

Maskbits in CIDR allow you to discover specific IP ranges within the network.

Example: /24 is the Maskbit for the Subnet 255.255.255.0, i.e. 192.168.0.1/24 = Range of IPs from 192.168.0.1 to 192.168.0.255.

  Subnet  

      CIDR Maskbit    

    Total IPs in Range    

    Number of Class C networks    

  255.255.255.255        

/32

1

1/256th

  255.255.255.240

/28

16

1/16th

  255.255.255.0

/24

256

1

  255.255.0.0

/16

65,536

256

 

Video Zone
OpManager Customer Videos
Altaleb Alshenqiti - Ministry of National Guard - Health Affairs
  
  •  IT Admin from "Royal flying doctor service", Australia
     Jonathan ManageEngine Customer
  •  Michael - Network & Tech, ManageEngine Customer
     Altaleb Alshenqiti - Ministry of National Guard - Health Affairs
  •  David Tremont, Associate Directory of Infrastructure,USA
     Todd Haverstock Administrative Director
  •  Donald Stewart, IT Manager from Crest Industries
     John Rosser, MIS Manager - Yale Chase Equipment & Services
 Pricing  Get Quote