[REBOL] Re: Ping?
From: holger:rebol at: 9-Feb-2001 10:33
On Fri, Feb 09, 2001 at 11:58:03AM -0600, Paul Tretter wrote:
> You cant. ICMP is not supported with REBOL which in the future I hope it is
> and it should be a part of /core and not some add on feature.
The problem is that on some platforms (Unix, QNX, some others) ICMP requires
root privileges, so on those platforms any REBOL scripts refering to it could
only be run by root or by a REBOL binary installed with setuid root.
ICMP as a protocol is really not all that useful. It is used internally by
UDP and TCP, mostly, to return errors, and those errors are reported back
by the stack to the socket, so they are already available in REBOL, as errors
at the port level.
The only potentially useful part of ICMP is "echo" (used by ping), and even
that is overrated. Ping does not work through proxies and some firewalls, so
in general it cannot be used to check for connectivity to a host. Ping is
a useful diagnostic tool for net admins, but IMHO has no place in applications
or scripting. Writing an application or a script that first tries to "ping"
a host before trying to create a connection to it is a typical beginner's
mistake. Those scripts break as soon as you switch platforms or network
settings, whereas scripts that simply try to create a connection work everywhere.
At the moment my feeling is that the marginal benefits of having ping in
REBOL do not outweigh the resulting compatibility problems in proxy
environments and across platforms.
--
Holger Kruse
[holger--rebol--com]
