CIDR and Useable IPs

When an IP address range is assigned to a dedicated server, it's done in CIDR format.

Using 138.128.17.168/29 as an example, below is a breakdown of the IP addresses in the CIDR format. The number of IPs available will change based on the range size.

Example 138.128.17.168/29 CIDR

• 138.128.17.168 Network

• 138.128.17.169 Gateway

• 138.128.17.170 Useable

• 138.128.17.171 Useable

• 138.128.17.172 Useable

• 138.128.17.173 Useable

• 138.128.17.174 Useable

• 138.128.17.175 Broadcast

• Cheat Sheet

Range Netmask Useable IPs

• /29 255.255.255.248 , 5 usable addresses

• /28 255.255.255.240 , 13 usable addresses

• /27 255.255.255.224 , 29 usable addresses

• /26 255.255.255.192 , 61 usable addresses

• /25 255.255.255.128 , 125 usable addresses

• /24 255.255.255.0 , 253 usable addresses