Intermittent connectivity loss with em(4)

Harry Duncan usr.src.linux at
Tue Oct 8 11:05:00 UTC 2019

On Tue, Oct 8, 2019 at 9:52 AM Morgan Wesström
<freebsd-database at> wrote:

> Thank you, Harry. No, Linux isn't an alternative. I run it on my clients
> but I feel much more comfortable with FreeBSD protecting my network. The
> Linux iptables/networking learning curve would be to much for me. :)

With you all the way there.

> Only what is currently the cable modem interface is experiencing this
> behaviour. I connect one of the others to my LAN and ssh to the machine
> that way and I never lose connection through ssh.

Interesting.... ssh ... so if ssh is failing through the cablemodem,
that points to something very very different. SSH is very fault
tolerant, as long as you don't try data entry, you can take down
networks and put them back up and have it resume as before.

If ssh session failure is what sparked this, then it is more likely
that you are falling victim to your ISP doing something like 4 to 6
NAT or 6 to 4 or even 4 to 4 NAT with RFC1913 on one side, and the far
side of the NAT not maintaining a constant IP through some load
balancing setup.

I've had some really weird experiences recently with the whole
ip4/ip6, like travelling to SE Asia and not able to connect into my
static ipv4 office network until I got a native to call the ISP and
then made some change, and I got onto the "whole" internet then. I
didn't look into it when I got what I wanted, but put it down to 6 to
4 nat/


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