Date: Fri, 23 May 2008 22:50:57 +0000 From: Kris Kennaway <kris@FreeBSD.org> To: Maxim Konovalov <maxim@macomnet.ru> Cc: freebsd-bugs@FreeBSD.org Subject: Re: kern/123881: Turning on TCP blackholing causes slow localhost connections Message-ID: <20080523225057.GE20868@hub.freebsd.org> In-Reply-To: <200805221410.m4MEA4lI093377@freefall.freebsd.org> References: <200805221410.m4MEA4lI093377@freefall.freebsd.org>
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On Thu, May 22, 2008 at 02:10:04PM +0000, Maxim Konovalov wrote:
> The following reply was made to PR kern/123881; it has been noted by GNATS.
>
> From: Maxim Konovalov <maxim@macomnet.ru>
> To: Tom Karpik <tom@tomkarpik.com>
> Cc: bug-followup@freebsd.org
> Subject: Re: kern/123881: Turning on TCP blackholing causes slow localhost
> connections
> Date: Thu, 22 May 2008 17:40:35 +0400 (MSD)
>
> > Turning on TCP blackholing (sysctl net.inet.tcp.blackhole=2) seems
> > to make connecting to some local services very slow.
> >
> > Example: telnet localhost 25 (default local Sendmail daemon after
> > fresh installation of FreeBSD)
> >
> > Sendmail responds with its greeting string right away if blackholing
> > is off. If it's turned on, it takes about 8-12 seconds for the
> > greeting to show up.
>
> Just an idea -- sendmail tries to use ident service and just timeouts
> on it due to tcp blackholing. To check this idea try to run e.g.
> inetd(8) auth service.
Failing that, use tcpdump to work out what is going on.
Kris
--
In God we Trust -- all others must submit an X.509 certificate.
-- Charles Forsythe <forsythe@alum.mit.edu>
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