11-stable mountd listens on port 993

Eric van Gyzen vangyzen at FreeBSD.org
Wed Feb 1 14:33:18 UTC 2017

On 02/01/2017 06:28, Peter Blok wrote:
> I just updated to 11-stable at 313042 and when I rebootted my system dovecot
> didn’t want to start because port 993 was already in use.
> Checked with lsof and it was mountd that was listening on this port. When I
> stopped mountd and started dovecot everything was fine. When I started mountd
> after this it worked ok.
> Next reboot everything was fine.
> Anybody know why mountd could have been listening to port 993?

Since mountd uses bindresvport_sa(3), the kernel chooses a port in the "low" 
range, configured via sysctl:

	net.inet.ip.portrange.lowlast: 600
	net.inet.ip.portrange.lowfirst: 1023

There is some randomness in the algorithm, so there is roughly a 1/424 chance of 
conflict.  You might use the -p flag to mountd or reduce lowfirst below 993.



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