DSL ssl ethernet but not wifi

[Paul Gilmartin]

CenturyLink DSL via Actiontec modem/router with wifi and
4 ethernet ports. Antique MacBook connected via wifi,
Raspberry Pi 3 Raspbian connected via either ethernet or wifi.

Apache server and HTTP client on RPi3 via wifi work fine with
client or server on MacBook.

ssl client or server on RPi3 and server or client on MacBook
work only with RPi3 on ethernet, but with wifi the client stalls
during initial handshaking:
[...]
debug1: Requesting no-more-sessions@openssh.com
debug1: Entering interactive session.
debug2: callback start
debug2: x11_get_proto: /usr/X11R6/bin/xauth list /tmp/launch-pMx7IK/org.x:0 2>/dev/null
Warning: No xauth data; using fake authentication data for X11 forwarding.
debug1: Requesting X11 forwarding with authentication spoofing.
debug2: channel 0: request x11-req confirm 0
debug2: client_session2_setup: id 0
debug2: channel 0: request pty-req confirm 1
debug2: channel 0: request shell confirm 1
debug2: fd 3 setting TCP_NODELAY
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug1: channel 0: free: client-session, nchannels 1
[... long time ...]
Killed by signal 15.

I have script ssh -vv traces on MacBook for ethernet and wifi
which are substantiallly similar until wifi stalls with no error
message until it times out.

Any ideas? My last resort would be CenturyLink support.

Thanks,
gil

[SurferTim]

Is your RPi connected to the localnet via wifi only? When attempting a ssh connection, does the RPi prompt for a password, then fails to respond? If this is the case, then open /etc/ssh/sshd_config with a text editor and add this to the end of the file and reboot.
IPQoS cs0 cs0

[Paul Gilmartin]

I can connect via either wifi or ethernet. Using wifi, ssh fails after accepting password:
> 587 $ time ssh -Y pi@192.168.0.6
> pi@192.168.0.6's password:
> Warning: No xauth data; using fake authentication data for X11 forwarding.
> Killed by signal 15.
[ I got tired of waiting and killed it from another session.]
> real 2m49.975s
> user 0m0.023s
> sys 0m0.015s

But HTTP works!
> 588 $ curl http://192.168.0.6 | wc
> % Total % Received % Xferd Average Speed Time Time Time Current
> Dload Upload Total Spent Left Speed
> 100 10701 100 10701 0 0 98k 0 --:--:-- --:--:-- --:--:-- 165k
> 368 933 10701

Now I plug in ethernet and try ssh again:
> 589 $ time ssh -Y pi@192.168.0.5
> pi@192.168.0.5's password:
> Warning: No xauth data; using fake authentication data for X11 forwarding.
>
> The programs included with the Debian GNU/Linux system are free software;
[Good from there on.]

Thanks,
gil

[Paul Gilmartin]

With an abundance of caution, I researched and chose the modal suggestion:
502 $ tail -7 /etc/ssh/sshd_config
# From:
# viewtopic.php?f=28&t=180916&p=1149798#p1149798
# https://github.com/guysoft/OctoPi/issues/294
# viewtopic.php?f=28&t=138631&p=1085534&h ... s#p1085534
# https://expresshosting.net/ssh-hanging-authentication/
# https://github.com/catmaker/chippy/wiki ... stallation
IPQoS 0x00

... which seems to work. Who woulda thunk it!?

Thanks again,
gil