Re: Abnormal behavior after bumping net.inet6.udp6.sendspace

On Tue, Jul 14, 2026 at 02:20:18PM +0200, Timo Buhrmester wrote:
> On amd64 10.1_STABLE, if I increase net.inet6.udp6.sendspace to 
> 209716 or larger, the machine in question ceases to serve new SSH
> sessions (the connection gets closed immediately) and attempting
> to restart sshd (via the system console) yields to something like
> "Bad address <NULL>" (or similar) and sshd not starting.

Is it this?

	% /sbin/sysctl -a | grep sbmax
	kern.sbmax = 262144

Setting the individual socket buffer sizes larger than sbmax (or too
close to it, because there is per-protocol overhead) has always caused
unobvious behavior, in my experience.  It may be that sbmax should
default to a larger value.

-- 
Thor Lancelot Simon	                                     [email protected]
  "Indeed, someone who is a citizen in a democracy is often not one in
   an oligarchy."
					- Aristotle, Politics III.1