problems caused by net.inet.tcp.blackhole=2

[Don Lewis]

On  8 Nov, Michal wrote:
> Hello,
> maybe someone will be able to help me with the problem. Namely setting 
> net.inet.tcp.blackhole=2 make samba to start very slow (90sec). Also 
> smbclient is slow. After samba starts there is no delay to connect from 
> the another machine with persistant local problems (smbclient). 
> Additionally the sysctl setting has veird impact on mozilla: trying to 
> write to web forms causes freezing of mozilla. Now setting 
> net.inet.tcp.blackhole=0 reverts all the problemsr: samba starts fast 
> and no problems with writing to the web forms.
> my system:
> FreeBSD 5.1-CURRENT #0: Thu Oct 30 17:49:13 EST 2003
> ports updated 11-08-03
> 
> I appreciate any suggestions

I looked at a similar problem that someone was having a while back.  It
appears that the problem is that this sysctl setting is suppressing the
sending of TCP RST packets which are needed to tear down dead
connections, and if one end of the connection thinks the connection is
still established, it is not possible to create a new connection between
the hosts that reuses the same addresses and ports as the old
connection.

Since the whole point of net.inet.tcp.blackhole=2 is to block the RST
packets that could allow the host to be scanned, I suspect you are
stuck.