Re: ECN: Clearing the air (fwd)

jamal
2001-01-28T12:20:16Z

On Sun, 28 Jan 2001, James Sutherland wrote:

> I'm sure we all know what the IETF is, and where ECN came from. I haven't
> seen anyone suggesting ignoring RST, either: DM just imagined that,
> AFAICS.

The email was not necessarily intended for you. You just pulled the pin.
There were people who made the suggestion that TCP should retry after a
RST because it "might be an anti-ECN path"

>
> The one point I would like to make, though, is that firewalls are NOT
> "brain-damaged" for blocking ECN: according to the RFCs governing
> firewalls, and the logic behind their design, blocking packets in an
> unknown format (i.e. with reserved bits set) is perfectly legitimate.

I dont agree that unknown format == reserved. I think it is bad design to
assume that. You may be forgiven if you provide the operator
opportunities to reset your assumptions via a config option.
It has nothing to do with a paranoia setting, just a bad design. Nothing
legit about that.

> Yes,
> those firewalls should be updated to allow ECN-enabled packets
> through. However, to break connectivity to such sites deliberately just
> because they are not supporting an *experimental* extension to the current
> protocols is rather silly.
>

This is the way it's done with all protocols. or i should say the way it
used to be done. How do you expect ECN to be deployed otherwise?
The internet is a form of organized chaos, sometimes you gotta make
these type of decisions to get things done. Imagine the joy _most_
people would get flogging all firewall admins who block all ICMP.
There is nothing silly with the decision, davem is simply a modern day
internet hero.

cheers,
jamal