ping 172.17.11220...Please explain why its pinging without decimal

manik.palekar · ‎06-03-2008

Dear frdz..

please explain why i am getting reply from below ip address even have not put decimal betn last two digits...

C:\ping 172.17.11220

Pinging 172.17.43.212 with 32 bytes of data:

Reply from 172.17.43.212: bytes=32 time=110ms TTL=125

Reply from 172.17.43.212: bytes=32 time=115ms TTL=125

Reply from 172.17.43.212: bytes=32 time=47ms TTL=125

Reply from 172.17.43.212: bytes=32 time=111ms TTL=125

Ping statistics for 172.17.43.212:

Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds:

Minimum = 47ms, Maximum = 115ms, Average = 95ms

Thanks in advance

hassaan_st · ‎06-03-2008

Dear fellow,

It worked in the following way.

The portion without decimal is '11220'.The system first converted '11220' into binary form '10101111010100'. Then it further broke this binary combination into two parts, starting from right hand side and collecting maximum 8 possible bits.

Which means,starting from the right hand side,it collected 8 bits,i.e. '11010100', and converted it into decimal form, i.e. '212'.

Then coming to the second part of binary numbers i.e. '101011', and converted it into decimal form, i.e. '43'.

In this way, it translated '11220' into '43.212'.

This is my understanding, waiting for some expert to confirm...

Hope it helps

Hassaan

Islamabad

cindylee27 · ‎06-05-2008

wow..something interesting ! that i never known off.. must try ! :)

Kevin Dorrell · ‎06-06-2008

Fascinating! I never knew that!

It works on a PC, and it works on Solaris. Not on a router though; that still gives "% Unrecognised host or address, or protocol not running."

I wondered whether there was some classful behavior here, but apparently not. ping 192.168.4865 really does ping 192.168.19.1. Even ping 3232240385 actually pings 192.168.19.1 !

Kevin Dorrell

Luxembourg

mohammedmahmoud · ‎06-06-2008

Hi All,

Nice post Hassan, to add a little bit you can also write it in hexa (but make sure that the number is preceded by 0x). Microsoft Windows TCP/IP applications such as ping, ftp and telnet accepts IP addresses in many forms, using the inet_addr() sockets function it translates IP addresses into the final 4-byte addresses. This function accepts an IP address in decimal, octal, or hexadecimal form.

BR,

Mohammed Mahmoud.