Re: mail service with no mx (was - Re: Computer systems blamed for feeble hurricane response?)

[Crist Clark <crist.clark () globalstar com>]

Adam McKenna wrote:
> On Tue, Sep 13, 2005 at 04:31:05PM -0700, william(at)elan.net wrote:
>
> > Telnet option negotiation is at Layer 7 after TCP connection has been
> > established. Firewalls typically don't operate at this level (TCP session
> > is Layer 4 if I remember right) and would refuse or reject (difference
> > type of ICMP response) based solely on attempt to connect to certain
> > ip or certain TCP/UDP port.
>
>
> Application layer firewalls have existed for at least 6 years.

AAAAAAAAAAAGGGGGGGGGGHHHHHH!

But the point is that you would still establish a TCP connection
before a MTA, firewall, IPS, or whatever could know it was telnet!
The FEMA address that started this whole thing was timing out. You
can tell the difference between a telnet filter and something
completely, silently blocking 25/tcp.

CAN THIS DIE NOW? Pulllleeeeeese...
--
Crist J. Clark                               crist.clark () globalstar com
Globalstar Communications                                (408) 933-4387