cannot connect

Sam Wilson Sam.Wilson at ed.ac.uk
Fri Sep 29 09:37:34 UTC 2006


In article <efi6t1$1hh7$1 at sf1.isc.org>,
 Mark Andrews <Mark_Andrews at isc.org> wrote:

> > Ping is generally a bad connection test. It uses ICMP which most firewalls 
> > wi
> > ll
> > block.
> 
> 	Any sane firewall will accept ICMP.  TCP and UDP don't
> 	operate correctly if you block ICMP.
> 
> 	The only problem with ICMP/ECHO was with directed broadcasts
> 	and any router purchased in the last 10 years has support
> 	for directed broadcasts off by default.

With respect there was also the ping of death, and many net admins fear 
DDoS with ping so think they should block it.

Sam



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