kern/123881: Turning on TCP blackholing causes slow localhost connections

[Maxim Konovalov]

The following reply was made to PR kern/123881; it has been noted by GNATS.

From: Maxim Konovalov <maxim at macomnet.ru>
To: Tom Karpik <tom at tomkarpik.com>
Cc: bug-followup at 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.
 
 -- 
 Maxim Konovalov