Re: ICMP dest-unreach in SYN_* states of TCP

[Jamie Lokier]

[EMAIL PROTECTED] wrote:
> > With ICMP it takes 75 seconds to abort, with RST it takes 0 seconds.
> 
> Well, report this to Compaq 8)8)8) It is bug.

:)

It is not that uncommon.  I just tried a few more:

                                ICMP delay    RST delay
                                ----------    ---------
  Digital V4.0                  75            0
  AIX version 4                 75            0
  HP-UX B.10.20 A               0             0
  Windows NT 4.0 SP4            45            1.5
  Linux 2.0.36                  0             0
  Linux 2.2.10                  0             0


The numbers are the time in seconds for the client to report "connection
refused" to the application layer.

Windows NT is unusual: even with RST, it tries the SYN 4 times, every
0.5 second.

So to report "no I've no daemon running here" to those systems and get a
quick response, you have to send RSTs instead of ICMPs.

-- Jamie
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