[Discuss] (ssh) Write failed: Broken pipe

[greg at freephile.com (Greg Rundlett (freephile))]

I've been experiencing a broken ssh tunnel that abruptly fails with "Write
failed: Broken pipe".  (Not the normal timeout experience of "Connection
reset by peer".)  Google and SO are failing to find me an answer.  (fb
posted a photo that is irrelevant and got many likes).

I don't have any problems with any other host that is configured the same
way, and I've tried various incantations of the /etc/ssh/sshd_config file
that are supposed to help.  Here is what I have currently on the server:

sudo grep -i alive /etc/ssh/sshd_config
TCPKeepAlive yes
ClientAliveInterval 60
ClientAliveCountMax 100000

I also have my Client configured to throw null packets at the server every
60 seconds.
grep -i alive ~/.ssh/config
ServerAliveInterval 60

At the OS level:
cat /proc/sys/net/ipv4/tcp_keepalive_time
7200

Any ideas what could cause this?

Greg Rundlett