Ping.pingecho

[john maclean]

Cisco.com don't normally allow pings so tracroutes and pings won't get
echo requests.


irb(main):003:0> Ping.pingecho('cisco.com', 10, 80)
=> true

How come this works and `ping` does not? From irb I see that Ruby's
ping uses a TCP echo. Also I've run tcpdump whilst running ping.echo
and could not determine the port that it uses. What port does Ruby's
Ping use?

 

[John Pritchard-williams]

Cisco.com don't normally allow pings so tracroutes and pings won't get
echo requests.


irb(main):003:0> Ping.pingecho('cisco.com', 10, 80)
=> true

How come this works and `ping` does not? From irb I see that Ruby's
ping uses a TCP echo. Also I've run tcpdump whilst running ping.echo
and could not determine the port that it uses. What port does Ruby's
Ping use?

check out:

http://www.noobkit.com/show/ruby/ruby/standard-library/ping/pingecho.html

According to this the 'echo' port.

grep'ing 'echo' in my /etc/services reveals this is port 7...apparently.
(UDP and TCP).