Why Linux can't visit public net?

[Waldher, Travis R]

>From: Edward King [mailto:zhangsc at neusoft.com] 
>	 
>	Then I use Windows OS,I configure IP address,gateway and DNS as
same as Red Hat Linux7.3,I found I can ping public net and visit public
net,like >follows:

Linx pings via ICMP, Windows via UDP. (IIRC)

A lot of places turn off ICMP echo requests to avoid denial of service
attacks.

So while you can't ping it, it really is there.