FW: ECHO Protocol

["David Hurst" <dhurst () lisletech com>]

The "echo" service referred to in the local services file is an old Unix
service typically implemented directly in inetd.  It listens on port 7 and
echos back any data sent to it.  Typically, the echo service should be
turned off because it performs no useful service and is a potential
vulnerability. 
 
This is completely different from the ICMP echo-request/echo-reply codes
used to implement ping. 
 
--DaveH         "Be Excellent to each other!"

-----Original Message-----
From: firewall-wizards-bounces () listserv cybertrust com
[mailto:firewall-wizards-bounces () listserv cybertrust com]On Behalf Of peng
liu
Sent: Monday, June 30, 2008 10:12 PM
To: Keith A. Glass; firewall-wizards () listserv cybertrust com
Subject: Re: [fw-wiz] ECHO Protocol


OK. This is the tricky part since ICMP is built basd on IP protocol and it
works on thesame layer as TCP/UDP. Then why my local services file contains:
 
echo                7/tcp
echo                7/udp
 
So the echo here is different than the Echo, Echo-reply protocol we are
talking here?
 
Regard,
Pengy

 
On 6/30/08, Keith A. Glass < salgak () speakeasy net> wrote:

Echo is a specific member of the ICMP family of protocols.  But not the ONLY
member. . .

Ping is typically Echo and Echo-reply.

Hope that clears it up


Keith

Security Geek  * Curmudgeon at Large *  Short on Sleep

On Thu Jun 26  6:00 , "peng liu"  sent:

> All,
>
> I am checking the ICMP protocol these days and some documents say that Ping
command in Windows uses ICMP protocol, while others say that Ping uses ECHO
protocol, which is through TCP port 7.
> So my question is which protocol is actually used by PING command in
Windows?
> Pengy




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