IP 192.168.1.0
Neem je masker 255.255.255.192
Het eerste groene getal pakken
Aftrekken van 256
256-192 = 64

128  64  32  16  8  4  2  1

De stappen van het eerste groene getal zullen 64 zijn

1e
192.168.1.0     NETID
192.168.1.1     LB
192.168.1.63     HB
192.168.1.64     BC

172.168.0.0
255.255.252.0
256-252=4

128  64  32  16  8  4  2  1

1e
172.168.0.0
172.168.0.1
172.168.4.254
172.168.4.255

IP        192.168.100.0
MASK      255.255.255.224

224 aftrekken 255
255.255.255.255
255.255.255.224 -
                         31


Trek een streep waar het vorige getal tussen past.
128      64     32|16     8    4    2    1


1 subnet
NETID    192.168.100.0
LB       192.168.100.1
HB       192.168.100.30
BC       192.168.100.31

2 subnet
NETID    192.168.100.32
LB       192.168.100.33
HB       192.168.100.62
BC       192.168.100.63

3 subnet
NETID    192.168.100.64
LB        192.168.100.65
HB        192.168.100.94
BC        192.168.100.95

4 subnet
NETID    192.168.100.96
LB        192.168.100.97
HB        192.168.100.126
BC        192.168.100.127

5 subnet
NETID    192.168.100.128
LB        192.168.100.129
HB        192.168.100.158
BC        192.168.100.159

6 subnet
NETID    192.168.100.160
LB        192.168.100.161
HB        192.168.100.190
BC        192.168.100.191

7 subnet
NETID    192.168.100.192
LB        192.168.100.193
HB        192.168.100.222
BC         192.168.100.223

8 subnet
NETID    192.168.100.224
LB        192.168.100.225
HB        192.168.100.253
BC        192.168.100.255

Subnet to calculate 192.168.1.X/25

/25 is on row 4 of our subnet table, this means the first 3 octets of our netmask are locked down and the last octect is unknown.
255.255.255.?

Our unknown octet has the value 128 as seen on the header of the Subnet Table.
This means our netmask is 255.255.255.128.

There are 128 hosts using this netmask as seen in Host Table.
2 of those are not usable, the broadcast (BC) and Network ID(NETID), this means there are 126 usable hosts in this subnet. We start counting these hosts from 0.
To define our range of usable hosts we will use the Lowest Usable (LU) and the Highest Usable (HU). This means our LU in this case will be 192.168.1.1 and our HU will be 192.168.1.126.

First Subnet
NETID     192.168.1.0
LU         192.168.1.1
HU        192.168.1.126
BC        192.168.1.127

Second Subnet
NETID     192.168.1.128
LU         192.168.1.129
HU        192.168.1.254
BC        192.168.1.255

Subnet to calculate 10.0.X.X/10

/10 is on row 2 of the subnet table, this means the first octet of our netmask are locked down to 255, the second octect is unknown and the rest are locked down to 0.
255.?.0.0

Our unknown octect has the value of 192 as seen in the header of the subnet table.
This means our netmask is 255.192.0.0.

There are 4194304 hosts using this netmask as seen in the host table.
2 of those are not usable, the broadcast (BC) and Network ID(NETID), this means there are 4194302 usable hosts in this subnet. We start counting these hosts from 0.
To define our range of usable hosts we will use the Lowest Usable (LU) and the Highest Usable (HU). Since this is a bigger range the Wildcard Mask can be used to make this easier.
To get our wildcard mask we inverse of our mask. Our wildcard mask is 0.63.255.255. See Wildcard Mask table.

This means our LU in this case will be 10.0.0.1 and our HU will be 10.63.255.254.

NETID     10.0.0.0
LU         10.0.0.1
HU        10.63.255.254
BC        10.63.255.255


NETID     10.64.0.0
LU         10.64.0.1
HU        10.127.255.254
BC        10.127.255.255

NETID     10.128.0.0
LU         10.128.0.1
HU        10.191.255.254
BC        10.191.255.255


NETID     10.192.0.0
LU         10.192.0.1
HU        10.255.255.254
BC        10.255.255.255

var d net.Dialer
d.Control = controlOnConnSetup

func controlOnConnSetup(network string, address string, c syscall.RawConn) error {
    return nil
}

// +build darwin dragonfly freebsd linux netbsd openbsd solaris
func controlOnConnSetup(c syscall.RawConn, addr Addr) error {
    var operr error
    fn := func(s uintptr) {
        operr = syscall.SetsockoptInt(int(s), syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
        if operr != nil {
            return
        }
        operr = syscall.SetsockoptInt(int(s), syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1)
        if operr != nil {
            return
        }
    }
    if err := c.Control(fn); err != nil {
        return err
    }
    if operr != nil {
        return operr
    }
    return nil
}

func controlOnConnSetup(network string, address string, c syscall.RawConn) error {
    var operr error
    fn := func(s uintptr) {
        handle := syscall.Handle(fd)
        operr = syscall.SetsockoptInt(handle, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
        if operr != nil {
            return
        }
    }
    if err := c.Control(fn); err != nil {
        return err
    }
    if operr != nil {
        return operr
    }
    return nil
}