ssh timeout question

Doug Denault doug at
Mon May 27 17:39:55 UTC 2019

I have broadband service from three different providers: Verizon (MD), Spectrum
(FL) and Shentel (VA) so I can say with  certainty that this is a function
of the modem. ssh connections FreeBSD <---> FreeBSD do not time out.

The timeouts appear to be a function of either NAT, DHCP or the number of active
connections the router can maintain. My current question is with Verizon FIOS
using the (latest??) modem AC1750 Wi-Fi (G1100). I have a home connection
(100 mbps) and a business connection (150 mbps) both have the same

On Verizon (biz) I currently have 24 active and inactive DHCP connections. I do
not appear to be hitting any limit here. Connections do not time out except on
any ssh connection running pine. The last time I checked pine it does not make
any imap requests except when checking for new mail. I'm using the default (150
secs). The other providers modems timeout connections so when I could not find a
keepalive setting that worked, I wrote a script to print a character every so
often (300 secs works for me).

Verizon happily times out pine connections in 2-3 hours. My keepalive script has
no effect. I am not sure of the minimum but around 3 hours seems to be the max.
Verizon of course says the do not time out connections. Probably true for their
network. Not for the modem IMO. Anyone with similar experience or know 

Douglas Denault
doug at
Voice: 301-217-9220
   Fax: 301-217-9277

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