Re: differences between win and unix tcp clients.

[Nuutti Kotivuori <naked@iki.fi>]

Joshua Goodall wrote:
> On Tue, Mar 16, 2004 at 09:12:01AM -0300, Fabiano Reis wrote:
>> Conclusion: I think this was because the Windows implementation of
>> TCP detects something different on this connection, maybe it
>> detects in some way that there is a filter on the server side and
>> this is why the time for the error message take so long to appear.
>
> Basically yes.  I wouldn't say that Windows "detects something
> different".   I would say that the Windows client isn't properly
> interpretating the ICMP Port Unreachable message.

Incorrect. Receiving an ICMP port unreachable message should not cause
a break in the connection attempt - it should be retried until SYN
timeout, at which point it can be informed that there was an ICMP port
unreachamble message received during the period.

So Windows is acting properly.

>> Am I right? Is there a workaround for this problem? I need to make
>> windows think that the server is really "down" and that is why i?m
>> writting to you people.
>
> try extending your REJECT option:
>
> -j REJECT --reject-with tcp-reset
>
> which should give you the desired result, in exchange for being
> a crude pseudo-rejection.

If you wish to get immediate reject responses, TCP reset is the only
way. It has nothing more or less crude than sending an ICMP.

-- Naked