<!DOCTYPE html><html><head><title></title><style type="text/css">p.MsoNormal,p.MsoNoSpacing{margin:0}
p.MsoNormal,p.MsoNoSpacing{margin:0}</style></head><body><div>This reminds me, I had a bizarre problem some months ago where I could reach some website over the 2.4 GHz wifi, but not from the 5 GHz wifi on the same router. I never did figure out why that happened.<br></div><div><br></div><div>Thomas<br></div><div><br></div><div>On Thu, 1 Apr 2021, at 19:02, Roy wrote:<br></div><blockquote type="cite" id="qt" style=""><p>My WiFi access point is dual band.<br></p><p>By default, the two bands appear as separate networks' not
allowed to communicate with each other, even though they are not
really.<br></p><p>Regards,<br></p><p>Roy Bamford.<br></p><p><br></p><p><br></p><div class="qt-moz-cite-prefix">On 31/03/2021 22:42, Andrew Kember
wrote:<br></div><blockquote type="cite" cite="mid:CA+D85xqwLSkPGZ-tLtWXtM=OG_arYiTKT3jnrNW6VHq4ZUmoOw@mail.gmail.com"><div dir="auto">Wow! That's such a bizarre situation! Good job
spotting the commonality though. Well worth a couple of repeated
checks, if only to observe the magic: "ssh-copy-id fails in the
kitchen, works in the living room. Now you see it, now you
don't!"<br></div><div dir="auto"><br></div><div dir="auto">I hope your brain-wax hardens again soon (that
sounds more odd than I was expecting). <br></div><div dir="auto"><br></div><div dir="auto">Andrew. <br></div><div><div><br></div><div class="qt-gmail_quote"><div dir="ltr" class="qt-gmail_attr">On Wed, 31 Mar 2021 at
21:59, <<a href="mailto:tengo@tutanota.de">tengo@tutanota.de</a>> wrote:<br></div><blockquote class="qt-gmail_quote" style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204, 204, 204);"><div><div>Update: The issue is fixed and the cause narrowed
down, but still confusing.<br></div><div><br></div><div>tl;dr It seems like a network issue, but I don't
know why.<br></div><div><br></div><div>Here's how I kind of fixed the issue...<br></div><div><br></div><div>My home network is a mix of 2GHz/5GHz WiFi and
hardwired machines. The Pi in question is on 5GHz WiFi
as was the laptop I was having problems with. <br></div><div><br></div><div>The other laptop that was not having problems was
hardwired. I wanted to sanity check this was working by
removing the ssh key and trying the ssh-copy-id again.
As the devices were in different rooms I brought them
all together in one room. This meant the laptop that was
not initially having problem was now using 5GHz WiFi (no
longer hardwired).<br></div><div><br></div><div>When I tried the ssh-copy-id it failed like the other
laptop. I also have a VM running on the laptop and this
encountered the same issue. I thought that since they
were both working, but now aren't, what has changed? The
network connection. I changed the WiFi from 5GHz to 2GHz
and everything worked fine! <br></div><div><br></div><div>I'm completely baffled as to why the ssh-copy-id
fails when the laptop(s) and Pi are on 5GHz WiFi, but
work when the laptops are hardwired or on the 2GHz WiFi.
Possibly the router?<br></div><div><br></div><div>I've not tried moving the Pi to 2GHz WiFi. I might
leave that for another day as my brain currently feels
like melting candle wax.<br></div><div><br></div><div>Thank you to everyone who got involved. It was pretty
cool learning a bit more about bash and using debug.<br></div><div><br></div><div>-----------<br></div><div><br></div><div><br></div><div><br></div><div>31 Mar 2021, 10:26 by <a href="mailto:dch.tai@gmail.com" target="_blank">dch.tai@gmail.com</a>:<br></div></div><div><blockquote style="border-left-width:1px;border-left-style:solid;padding-left:10px;margin-left:5px;border-left-color:rgb(147, 163, 184);"><div dir="ltr"><div>That's a good point Andrew, well spotted. Not so
off-the-wall as you'd think.<br></div><div><br></div><div>Though Tengo did say there's no problem from the
other laptop... which makes it look like a
client-side problem...<br></div><div><br></div><div>@Tengo - quid of the contents in .ssh/config ?<br></div><div><div><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div><div><br></div><div><br></div><div>===<br></div><div>Tai
Kedzierski<br></div></div><div><br></div><div>EdLUG
Maintainer: <a href="https://edlug.gitlab.io/" rel="noopener noreferrer" target="_blank">https://edlug.gitlab.io/</a><br></div></div><div><br></div><div>Edinburgh
Language
Meetup
Organiser<br></div><div><a href="https://www.meetup.com/Edinburgh-Language-Exchange-Meetup-Group/" rel="noopener
noreferrer" target="_blank">https://www.meetup.com/Edinburgh-Language-Exchange-Meetup-Group/</a><br></div><div><div dir="ltr"><br></div><div dir="ltr"><span style=""><span class="size" style="font-size:10px;"><i>Open Source Free Software is a matter of
liberty, not
price.</i><br> <a href="https://www.fsf.org/about/what-is-free-software" rel="noopener
noreferrer" target="_blank">https://www.fsf.org/about/what-is-free-software</a> </span></span><span style=""><span class="size" style="font-size:13px;"></span></span></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div><div><br></div></div></div><div><br></div><div><div dir="ltr">On Tue, 30 Mar 2021 at 21:58, Andrew
Kember <<a href="mailto:andrew@kember.net" rel="noopener noreferrer" target="_blank">andrew@kember.net</a>>
wrote:<br></div><blockquote style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204, 204, 204);"><div dir="auto">Time for a left-field idea. This is
PiOS right? Raspberry pi OS?<br></div><div dir="auto"><br></div><div dir="auto">When I log in with the default user
(pi) using any method, and still have the default
password set on that account, it triggers a
message on the console telling me to change the
password. <br></div><div dir="auto"><br></div><div dir="auto">Now, that surely should only come up
in an interactive shell, it doesn't ask for any
input either, but I think it is specific to PiOS,
so ... maybe it's badly implemented somehow. <br></div><div dir="auto"><br></div><div dir="auto">Question: do you still have the
default password set, and does this problem still
happen if you've changed it?<br></div><div dir="auto"><br></div><div dir="auto">(Told you it was a bit
off-the-wall!)<br></div><div dir="auto"><br></div><div dir="auto">AK <br></div><div><div><br></div><div><div dir="ltr">On Tue, 30 Mar 2021 at 21:48,
Gordon Gray <<a href="mailto:gordo.gray@gmail.com" rel="noopener noreferrer" target="_blank">gordo.gray@gmail.com</a>>
wrote:<br></div><blockquote style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204, 204, 204);"><div dir="auto">Hi all. I’m enjoying this
thread. My approach to problem solve would
be the one Tai described: run the commands
from the script manually. <br></div><div dir="auto"><br></div><div dir="auto">One thing I noticed though is
this line in the debug output<br></div><div dir="auto"><br></div><div dir="auto"><span style="word-spacing:1px;border-top-color:rgb(49, 49, 49);border-right-color:rgb(49, 49, 49);border-bottom-color:rgb(49, 49, 49);border-left-color:rgb(49, 49, 49);color:rgb(49, 49, 49);"><span style=""><span class="font" style="font-family:monospace;">debug1:
Sending env LANG = en_GB.UTF-8</span></span></span><br></div><div dir="auto"><span style="word-spacing:1px;border-top-color:rgb(49, 49, 49);border-right-color:rgb(49, 49, 49);border-bottom-color:rgb(49, 49, 49);border-left-color:rgb(49, 49, 49);color:rgb(49, 49, 49);"><span style=""><span class="font" style="font-family:monospace;"></span></span></span><br></div><div dir="auto" style="background-color:rgba(0, 0, 0, 0);border-top-color:rgb(255, 255, 255);border-right-color:rgb(255, 255, 255);border-bottom-color:rgb(255, 255, 255);border-left-color:rgb(255, 255, 255);color:rgb(255, 255, 255);"><span>I
suspect you might need to edit your locale
as described here:</span><br></div><div dir="auto" style="background-color:rgba(0, 0, 0, 0);border-top-color:rgb(255, 255, 255);border-right-color:rgb(255, 255, 255);border-bottom-color:rgb(255, 255, 255);border-left-color:rgb(255, 255, 255);"><span></span><br></div><div dir="auto" style="background-color:rgba(0, 0, 0, 0);border-top-color:rgb(255, 255, 255);border-right-color:rgb(255, 255, 255);border-bottom-color:rgb(255, 255, 255);border-left-color:rgb(255, 255, 255);"><span><div><a href="https://unix.stackexchange.com/questions/347914/how-to-set-lc-all-en-gb-utf-8-in-raspbian" rel="noopener noreferrer" target="_blank">https://unix.stackexchange.com/questions/347914/how-to-set-lc-all-en-gb-utf-8-in-raspbian</a><br></div><div dir="auto"><br></div><div dir="auto">Cheers,<br></div><div dir="auto">Gordon<br></div><div><br></div></span></div><div><div><div dir="ltr"><br></div><div dir="ltr">On Tue, 30 Mar 2021 at
21:39, <<a href="mailto:tengo@tutanota.de" rel="noopener noreferrer" target="_blank">tengo@tutanota.de</a>>
wrote:<br></div><blockquote style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204, 204, 204);"><div><div>Hi Nick,<br></div><div><br></div><div>Both are 1500.<br></div><div><br></div><div>Regards,<br></div><div><br></div><div>John<br></div><div><br></div><div>-----------<br></div><div><br></div><div><br></div><div><br></div><div>30 Mar 2021, 21:22 by <a href="mailto:nick@dischord.org" rel="noopener noreferrer" target="_blank">nick@dischord.org</a>:<br></div></div><div><blockquote style="border-left-width:1px;border-left-style:solid;padding-left:10px;margin-left:5px;border-left-color:rgb(147, 163, 184);"><div dir="ltr"><div dir="ltr"><div>Can you check network
interface MTU settings? A
simple 'ip li' should do the
trick. Make sure they're all
the same; 1500 being the
default for Ethernet, or if
you've enabled jumbo frames
then perhaps 9000. The key
thing is that they're all
exactly the same.<br></div><div><div><br></div><div><div dir="ltr"><div dir="ltr"><div>-- <br></div><div><div><br></div><div>-Nick<br></div></div></div></div></div><div><br></div></div></div><div><br></div><div><div dir="ltr">On Tue, 30 Mar
2021 at 21:08, <<a rel="noopener noreferrer" href="mailto:tengo@tutanota.de" target="_blank">tengo@tutanota.de</a>>
wrote:<br></div><blockquote style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204, 204, 204);"><div><div>Thanks for all the
replies.<br></div><div><br></div><div>Quiet a lot of
discussion and suggestions
and things I don't quite
understand. I'm willing
to try more
troubleshooting, but for
now here's a copy of the
output from ssh-copy-id
with DEBUG3 - <a rel="noopener
noreferrer" href="https://file.re/2021/03/30/ssh-copy-id-debug3/" target="_blank">https://file.re/2021/03/30/ssh-copy-id-debug3/</a> . It will be available for
24 hours. <br></div><div><br></div><div>@Tai - Thanks for your
suggestion. I'm not
looking for a work around
as I think this issue is
also stopping me from
using Ansible to manage
the Pi. <br></div><div><br></div><div>For example, if I
manually copy the key to
the Pi I can SSH without
any issues. However, if I
run a simple Ansible
ad-hoc command using the
"ping" module it hangs
too. This module makes its
connection with SSH and
I'm using the same account
(pi). I also encountered
issues when I tried the
ssh extension in VS code
too. Not too bothered
about VS code extension
(in preview), but it's
also using ssh and
failing.<br></div><div><br></div><div>None of this is a
problem from my other
laptop.<br></div><div><br></div><div>-----------<br></div><div><br></div><div><br></div><div><br></div><div>30 Mar 2021, 16:48 by <a rel="noopener
noreferrer" href="mailto:dch.tai@gmail.com" target="_blank">dch.tai@gmail.com</a>:<br></div><blockquote style="border-left-width:1px;border-left-style:solid;padding-left:10px;margin-left:5px;border-left-color:rgb(147, 163, 184);"><div dir="ltr"><div>Back on track :-)<br></div><div><br></div><div>You could try
running as Geetam
suggested <br></div><div><br></div><div> ssh-copy-id -o
LogLevel=DEBUG3 pi@$IP<br></div><div><br></div><div>for even more
verbose output
(equivalent to running
ssh -vvv ...)<br></div><div><br></div><div><br></div><div>If you "just want
it to work", and
regular SSH seems to
work, you could
instead run this:<br></div><div><br></div><div>
akeysfile=".ssh/authorized_keys"<br></div><div> ssh pi@"$IP"
"cd ; umask 077 ;
mkdir -p .ssh
&& touch
$akeysfile &&
cat >>
$akeysfile" <
"$HOME/.ssh/id_rsa.pub"<br></div><div><br></div><div>This is the
simplified version of
what ssh-copy-id tries
to do, except the
latter does extra
checking of various
things. This one just
bluntly and forcibly
append your existing
public id content to
the remote auth keys
file. Manually adding
a key is what I do to
grant access to other
people onto boxes,
this technique is
fine.<br></div><div><br></div><div><br></div><div>From reading the
ssh-copy-id script, I
can see it does some
complex jiggery-pokery
with trying to read
the public key file
and determine if it's
the latest, if it's
already over on the
other side, etc. That
it prompts means
there's a connection.
That it hangs on that
command, makes it
sound like the printf
isn't doing what is
expected and the `cat`
being run on the
remote side isn't
receiving data, OR
that the server is
trying to prompt you
somehow but you are
not seeing that
prompt, which is
unlikely but I've seen
weirder, I'm sure.<br></div><div><br></div><div>Which leads me to
still suspect as
Andrew Kember
mentioned that X11
might be getting in
the way, or some other
SSH option causing the
client to wait for the
server to supply
something and the two
are in disagreement.
Once sanitized, could
you send the contents
of ~/.ssh/config (or,
look there to see if
there is any mention
of xauth or X11 ?) I
most often don't have
anything in that
config, so if it's
heavily populated, you
might need to weed
around it.... or, try
renaming it
temporarily so that it
does not take effect.<br></div><div><div><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div><br></div><div><br></div><div>Note that
if you are
somehow trying
to include
ssh-copy-id
inside as a
recipient in a
pipe, it will
play silly
diggers with
you, so don't
pipe anything
into the
script.<br></div><div><br></div><div><br></div><div>Good
luck, cod
speed.<br></div><div><br></div><div><div><br></div><div><br></div><div>===<br></div><div>Tai
Kedzierski<br></div></div><div><br></div><div>EdLUG
Maintainer: <a href="https://edlug.gitlab.io/" rel="noopener noreferrer" target="_blank">https://edlug.gitlab.io/</a><br></div></div><div><br></div><div>Edinburgh
Language
Meetup
Organiser<br></div><div><a href="https://www.meetup.com/Edinburgh-Language-Exchange-Meetup-Group/" rel="noopener
noreferrer" target="_blank">https://www.meetup.com/Edinburgh-Language-Exchange-Meetup-Group/</a><br></div><div><div dir="ltr"><br></div><div dir="ltr"><span><span><span style=""><span class="size" style="font-size:10px;"><i>Open Source Free Software is a matter of
liberty, not
price.</i><br> <a href="https://www.fsf.org/about/what-is-free-software" rel="noopener
noreferrer" target="_blank">https://www.fsf.org/about/what-is-free-software</a></span></span></span></span><span><span><span style=""><span class="size" style="font-size:13px;"></span></span></span></span></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div><div><br></div></div></div><div><br></div><div><div dir="ltr">On Tue,
30 Mar 2021 at 16:05,
Justin B Rye <<a href="mailto:justin.byam.rye@gmail.com" rel="noopener
noreferrer" target="_blank">justin.byam.rye@gmail.com</a>>
wrote:<br></div><blockquote style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204, 204, 204);"><div>Robert McWilliam
wrote:<br></div><div>> On Tue, 30
Mar 2021, at 13:09,
Justin B Rye wrote:<br></div><div>>>>
pstree -sup $(ps aux
| grep sshd | awk
'{print $2}' | sort
-n | head -n 1)<br></div><div>>>> <br></div><div>>> <br></div><div>>> As a
general rule of
thumb, any
complicated pipeline
like that is<br></div><div>>> really a
job for pgrep (which
you probably get in
the same package as<br></div><div>>> ps).
The above simplifies
down to<br></div><div>>> <br></div><div>>> pstree
-sup $(pgrep sshd)<br></div><div>> <br></div><div>> You've
thrown away a bit
too much of the
pipeline there:
pgrep will<br></div><div>> give
multiple results if
there are SSH
sessions and only
want one for<br></div><div>> pstree so
need the head part
(and possibly the
sort - I think ps
and<br></div><div>> pgrep will
give processes in
order of PID without
having to sort but<br></div><div>> chucking
sort in the pipeline
was quicker than
checking).<br></div><div><br></div><div>When you want the
oldest, that's
"pgrep -o sshd";
taking the lowest<br></div><div>number will mess
up if the PIDs wrap
around. Mind you, I
was<br></div><div>surprised by how
hard it has become
to do this - I
hadn't previously<br></div><div>noticed that
/proc/sys/kernel/pid_max
has gone up from
32,768 on my<br></div><div>old stable
desktop to 4,194,304
on my testbed
machine!<br></div><div><br></div><div>[...]<br></div><div>> Yes, just
explaining where to
manually copy the
PID from is probably<br></div><div>> easier, but
where's the fun in
that :) <br></div><div><br></div><div>I hope you'll
forgive me my
addiction to shell
golf then!<br></div><div>-- <br></div><div>Justin B Rye<br></div><div><a rel="noopener
noreferrer" href="http://jbr.me.uk/" target="_blank">http://jbr.me.uk/</a><br></div><div><br></div><div>-- <br></div><div>EdLUG mailing
list<br></div><div><a href="mailto:EdLUG@mailman.lug.org.uk" rel="noopener
noreferrer" target="_blank">EdLUG@mailman.lug.org.uk</a><br></div><div><a rel="noopener
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