127.0.0.1

Index

127.0.0.1

192.168.1.1

192.168.0.1

192.168.2.1

192.168.1.254

192.168.1.100

192.168

192.168.1

192.168.100.1

192.168.0.2

192.168.1.101

192.168.0.100

192.168.1.102

192.168.11

192.168.254.254

192.168.0.254

192.168.0.101

192.168.1.250

192.168.1.103

192.168.2.254

IP Address Shortage

A private IP address

127.0.0.1 is your own computer

Each internet device, except those build for special purposes, have an IP address 127.0.0.1. This IP address is not visible from outside, as it is routed to the loopback interface of the device. The IP address 127.0.0.1 is known also as localhost or localhost.localdomain. It is however possible for someone to send IP packets with source address 127.0.0.1 and they still to be routed to your computer. Your computer will not send back packets to the originator, as they will be routed to the loopback interface.

In binary form it is 01111111000000000000000000000001 or 0b01111111000000000000000000000001.

In hexadecimal format it is 7F000001 or 0x7F000001.

As the netmask of those networks is usually 8 bits, the address is written also as 127.0.0.1/8 or 127.0.0.1/255.0.0.0. All IP addresses starting with 127, ranging from 127.0.0.1 to 127.255.255.255 are routed to the loopback interface.

# ping -c1 127.0.0.1

PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.

64 bytes from 127.0.0.1: icmp_req=1 ttl=60 time=0.230 ms

--- 127.0.0.1 ping statistics ---

1 packets transmitted, 1 received, 0% packet loss, time 0ms

rtt min/avg/max/mdev = 0.230/0.230/0.230/0.000 ms

# traceroute -n 127.0.0.1

traceroute to 127.0.0.1 (127.0.0.1), 3 hops max, 60 byte packets

1 127.0.0.1 0.229 ms 0.143 ms 0.121 ms