Re: Tool for testing filters?

[Chris Brenton <cbrenton () sover net>]

Fernando da Silveira Montenegro wrote:

> Does anybody
> know of a good tool we can use to check if the path from the local ISP
> to the corporate firewall) is clear of packet filters that would block
> VPN traffic (TCP/1723, TCP/420, SWIPE, IPSEC, GRE, ...)?

How about:telnet target.foobar.com 1723
telnet target.foobar.com 420
etc...

If you can establish a connection, the path is clear. If not, someone is
blocking the port. If you run a program such as port mapper or simply create
a service that cats a text file, you can even set it up so the destination
system responds with a message.

This will not give you the informative feedback that traceroute would, but
then again TCP was not really designed for maintenance.

Hope this helps,
Chris
--
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cbrenton () sover net

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