What is CIDR
- Class inter-domain routing
- IP address scheme that improves the allocation of IP addresses.
- Helps in slowing growth of IP tables
- CIDR is based on variable-length subnet masking (VLSM)
- VLSM allows it to define prefixes of arbitrary length making it much more efficient.
- CIDR IP addresses are composed of two sets of numbers.
- The network address is written as a prefix
- The second part is a suffix that indicates how many bits are in the entire address
- ex: 192.255.255.255/12
- The lower suffix number represents a higher number of IP addresses. 5 IP addresses are always reserved for internal use.
- 10.0.0.0/8 --> 16M IP addresses, 10.0.0.0 to 10.255.255.255
- 10.0.0.0/16 --> 65K IP addresses, 10.0.0.0 to 10.0.255.255
- 10.0.0.0/24 --> 256 IP addresses, 10.0.0.0 to 10.0.0.255