Doubt In default time to live (TTL) 255?

Solution 1:

Here's a relevant quote from the ping manpage:

TTL DETAILS The TTL value of an IP packet represents the maximum number of IP routers that the packet can go through before being thrown away. In current practice you can expect each router in the Internet to decrement the TTL field by exactly one.

The TCP/IP specification recommends setting the TTL field for IP packets to 64, but many systems use smaller values (4.3BSD uses 30, 4.2BSD used 15).

And to quote RFC 1700:

The current recommended default time to live (TTL) for the Internet Protocol (IP) is 64.

Solution 2:

The maximum TTL is 255, but it is not the default. The default value depends on the operating system as you can see here.

For example, look at pings to 127.0.0.1 in Windows vs Linux:

My windows 7:

My Linux machine:

So it seems that you're getting replies from a machine whose default is 64.