kern/121668: connect randomly fails with EPERM with some pf rules

[Max Laier]

The following reply was made to PR kern/121668; it has been noted by GNATS.

From: Max Laier <max at love2party.net>
To: bug-followup at freebsd.org,
 lfrigault at agneau.org
Cc:  
Subject: Re: kern/121668: connect randomly fails with EPERM with some pf rules
Date: Thu, 13 Mar 2008 20:26:39 +0100

 > sysctl net.inet.tcp.nolocaltimewait=1
 > not needed, but helps to reproduce the problem with client and server
 > on the same computer.
 
 Okay, now this is just asking for trouble.  pf does thorough checks on TCP 
 states, one of which is to enforce the 2MSL quite time before port reuse.  
 If you set above sysctl you specificly ask FreeBSD to break that rule and 
 thus cause pf to bark.
 
 You can also hit the issue if you have a large number of (consecutive) 
 connections between two hosts (e.g. [poorly configured] squid -> 
 www-backends, mysql, ...).  The sollution is to:
 
  1) Reduce the connection spree and use one permanent connection
  2) Increase the ephemeral port range net.inet.ip.portrange.hi{first,last}
  3) Decrease the pf state timeout tcp.{closing,closed} in order to relax 
 the check.  You can do this globaly and on a per-rule basis.
 
 -- Max