joyent/node — pull request #2998 by shigeki (2012-03-23 10:02:12+00:00)
Title: doc: Fix default dgram multicast ttl to 1

On most systems, default ip multicast ttl is not 64 but 1 to be restricted on the local subnet.

Linux: http://man7.org/linux/man-pages/man7/ip.7.html

````
IP_MULTICAST_TTL (since Linux 1.2)
Set or read the time-to-live value of outgoing multicast packets for this socket. It is very important for multi‐
cast packets to set the smallest TTL possible. The default is 1 which means that multicast packets don't leave the local network unless the user program explicitly requests it.
````

Windows: http://support.microsoft.com/kb/257460/en-us

````
winsock.h
#define IP_DEFAULT_MULTICAST_TTL 1 /* normally limit m'casts to 1 hop */
````