Re: Computer systems blamed for feeble hurricane response?

[Mike Tancsa <mike () sentex net>]

At 03:50 PM 13/09/2005, Joseph S D Yao wrote:

> Oh, and also ... please consider that some firewalls try to discern
> whether the connection on port 25 is from a mail server or from Telnet.
> While I mourn the simplicity of manual debugging of such sites, it
> remains that: the fact that you can't TELNET HOST.DOMAIN 25 doesn't mean
> that there's no mail service there.

Making a network connection using the application "telnet" vs the 
application "sendmail" (or whatever MTA one uses) seems to be the 
same when doing a tcpdump on the data.  I am not sure how a firewall 
would know -- purely at the network layer -- what the other side's 
application was/is that initiated the connection.  Yes, the other end 
could try and connect back to the host, but there is no 2 way traffic 
as the 3way handshake is not completing and I dont see any other 
traffic coming back from that host attempting to discern any info.

        ---Mike