On Tue, 2003-11-25 at 11:08, Alan Dayley wrote:
> I have setup my at home email server for external access on an odd, high 
> port number.  It has been working well with dynamic DNS from my domain 
> provider and everything.  Then, it suddenly stopped answering and I can 
> get into it, even with the specific IP.
> 
> A brief check of all configuration and operation this morning showed 
> that all is supposedly well on my end.  Is there a way I can tell if my 
> ISP is suddenly blocking the ports?
----
You have some other answers but the way I generally check things out is
typically with telnet & traceroute 

traceroute would allow you to see if it breaks before it reaches the
destination...

traceroute -n -p high_port xxx.xxx.xxx.xxx

telnet xxx.xxx.xxx.xxx high_port_#

of course you need a machine from 'off' the network to test them - i.e.
ssh connection

Craig