~/ryan
Tools

CIDR Calculator

Solve any IP/prefix with the group-size table: find the prefix, read the group size above it, and count by that number in the right octet. Network, broadcast, and host range fall out of the count.

/
Try
Group size1286432168421
Subnet128192224240248252254255
CIDR/25/26/27/28/29/30/31/32

Count by 8 in the 4th octet (your value: 37)

16243237 ←404856
Mask255.255.255.248
Network ID10.1.1.32
Broadcast10.1.1.39
First host10.1.1.33
Last host10.1.1.38
Next network10.1.1.40
# IPs8 (6 usable)
Wildcard0.0.0.7

The method

  1. Find /29 in the CIDR row. Above it, the group size is 8 and the subnet value is 248, so the mask is 255.255.255.248.
  2. Count by 8 in the 4th octet. 37 falls between 32 and 40.
  3. The lower number gives the Network ID: 10.1.1.32.
  4. The upper number gives the next network: 10.1.1.40. The broadcast is one address before it: 10.1.1.39.
  5. First host is network + 1 (10.1.1.33), last host is broadcast − 1 (10.1.1.38).
  6. # IPs = 8 = 8, and 6 of them are usable.