Local Broadcast and Loopback Address
Local Broadcast Address:
Local Broadcast Address is used to communicate with all the devices on a local network. It is represented by 255.255.255.255 or 11111111.11111111.11111111.11111111 in binary.
A broadcast address is used by hosts to request IP addresses from the DHCP(Dynamic Host Configuration Protocol) server. The host sends a broadcast to the broadcast address to request an IP address and in turn the DHCP server allocates an IP address from the pool of IP addresses.
By default, local broadcast address is always dropped by routers and layer 3 switches; but one can always override this by configuring the device with DHCP forwarding or DHCP relay.
Local Loopback Address:
Local Loopback Address is used to let a system send a message to itself to make sure that TCP/IP stack is installed correctly on the machine.
In IPv4, IP addresses that start with decimal 127 or that has 01111111 in the first octet are loopback addresses(127.X.X.X). Typically 127.0.0.1 is used as the local loopback address.
This leads to the wastage of many potential IP addresses. But in IPv6 ::1 is used as local loopback address and therefore there isn’t any wastage of addresses.