[c-nsp] Port Traceroute utility?

[bill fumerola]

On Tue, Nov 06, 2007 at 01:02:52PM -0600, Jonathan Charles wrote:
> This is going to sound weird, but I am looking for a utility that will
> let me tracroute on a specific port to see if and where a port is
> being blocked on a network...

http://michael.toren.net/code/tcptraceroute/

> I run into issues where customers have ACLs on their network (that
> they don't know about) and it is causing network failures... (usually
> TFTP...)...

that's udp, so tcptraceroute won't work. detecting open/closed/filtered
udp ports typically requires specific knowledge about the network and
possible filtering/blocking going on. different techniques work for
different networks. once the equation gets big enough, no techniques may
work.

often end-to-end testing (e.g. a sniffer or tcpdump at both ends) is the
only real solution.


-- bill