Indicia

/29 subnet (255.255.255.248)

A /29 network has 8 addresses, of which 6 can be given to hosts after the network and broadcast addresses. A small segment: a few dozen hosts, such as a management VLAN, a DMZ or a small office network.

CIDR notation
/29
Subnet mask
255.255.255.248
Wildcard mask
0.0.0.7
Binary mask
11111111.11111111.11111111.11111000
Total addresses
8
Usable hosts
6
Example network
192.168.1.0/29
Example usable range
192.168.1.1 – 192.168.1.6
/29 networks in a /24
32

Calculate a /29 for your own address

192.168.1.0/24 split into /29 networks

NetworkUsable rangeBroadcast
192.168.1.0/29192.168.1.1 – 192.168.1.6192.168.1.7
192.168.1.8/29192.168.1.9 – 192.168.1.14192.168.1.15
192.168.1.16/29192.168.1.17 – 192.168.1.22192.168.1.23
192.168.1.24/29192.168.1.25 – 192.168.1.30192.168.1.31
192.168.1.32/29192.168.1.33 – 192.168.1.38192.168.1.39
192.168.1.40/29192.168.1.41 – 192.168.1.46192.168.1.47
192.168.1.48/29192.168.1.49 – 192.168.1.54192.168.1.55
192.168.1.56/29192.168.1.57 – 192.168.1.62192.168.1.63
192.168.1.64/29192.168.1.65 – 192.168.1.70192.168.1.71
192.168.1.72/29192.168.1.73 – 192.168.1.78192.168.1.79
192.168.1.80/29192.168.1.81 – 192.168.1.86192.168.1.87
192.168.1.88/29192.168.1.89 – 192.168.1.94192.168.1.95
192.168.1.96/29192.168.1.97 – 192.168.1.102192.168.1.103
192.168.1.104/29192.168.1.105 – 192.168.1.110192.168.1.111
192.168.1.112/29192.168.1.113 – 192.168.1.118192.168.1.119
192.168.1.120/29192.168.1.121 – 192.168.1.126192.168.1.127
192.168.1.128/29192.168.1.129 – 192.168.1.134192.168.1.135
192.168.1.136/29192.168.1.137 – 192.168.1.142192.168.1.143
192.168.1.144/29192.168.1.145 – 192.168.1.150192.168.1.151
192.168.1.152/29192.168.1.153 – 192.168.1.158192.168.1.159
192.168.1.160/29192.168.1.161 – 192.168.1.166192.168.1.167
192.168.1.168/29192.168.1.169 – 192.168.1.174192.168.1.175
192.168.1.176/29192.168.1.177 – 192.168.1.182192.168.1.183
192.168.1.184/29192.168.1.185 – 192.168.1.190192.168.1.191
192.168.1.192/29192.168.1.193 – 192.168.1.198192.168.1.199
192.168.1.200/29192.168.1.201 – 192.168.1.206192.168.1.207
192.168.1.208/29192.168.1.209 – 192.168.1.214192.168.1.215
192.168.1.216/29192.168.1.217 – 192.168.1.222192.168.1.223
192.168.1.224/29192.168.1.225 – 192.168.1.230192.168.1.231
192.168.1.232/29192.168.1.233 – 192.168.1.238192.168.1.239
192.168.1.240/29192.168.1.241 – 192.168.1.246192.168.1.247
192.168.1.248/29192.168.1.249 – 192.168.1.254192.168.1.255

In firewall rules and investigations

A /29 rule matches every address from 192.168.1.0 to 192.168.1.7. In Cisco ACLs the same range is written with the wildcard mask 0.0.0.7. When an alert names an IP, checking whether it falls inside a known /29 (your own network, a cloud provider’s published range or a blocked range) is often the quickest first step.