• WiFi dropping on Pi4, what to do?

    From bob prohaska@3:770/3 to All on Fri Dec 10 01:54:50 2021
    Following a RasPiOS upgrade yesterday, a Pi4 seems to be dropping
    its wifi connection considerably more than usual. In the past, this
    has been accompanied by signal strength readings below 70% on wavemon.
    Now, the signal strength is over 80% and the machine is still dropping
    the connection. Cellphones have no problem connecting.

    So far, the remedy seems to be turning wifi off and then back on. Are
    there any tricks that might help sort out what's wrong? There are many
    wifi networks visible to the Pi, but I think mine is the strongest.

    Thanks for reading,

    bob prohaska
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From Jim Jackson@3:770/3 to bob prohaska on Fri Dec 10 18:51:54 2021
    On 2021-12-10, bob prohaska <bp@www.zefox.net> wrote:
    Following a RasPiOS upgrade yesterday, a Pi4 seems to be dropping
    its wifi connection considerably more than usual. In the past, this
    has been accompanied by signal strength readings below 70% on wavemon.
    Now, the signal strength is over 80% and the machine is still dropping
    the connection. Cellphones have no problem connecting.

    So far, the remedy seems to be turning wifi off and then back on. Are
    there any tricks that might help sort out what's wrong? There are many
    wifi networks visible to the Pi, but I think mine is the strongest.

    The solution is use wired connection :-)

    sorry I can't really help, I've never used wifi on my several Pi's. I've
    seen several complaints about the reliability of the wifi. Have you
    searched the Pi Forum for any hints?
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From Marco Moock@3:770/3 to All on Fri Dec 10 20:22:11 2021
    Am Freitag, 10. Dezember 2021, um 01:54:50 Uhr schrieb bob prohaska:

    Following a RasPiOS upgrade yesterday, a Pi4 seems to be dropping
    its wifi connection considerably more than usual. In the past, this
    has been accompanied by signal strength readings below 70% on wavemon.
    Now, the signal strength is over 80% and the machine is still dropping
    the connection. Cellphones have no problem connecting.

    Is it the same power?
    This is the relevant size, maybe they updated the database for max
    allowed power per country and this changed something.
    Be aware that need to check the local rules of your residence for the
    laws about max. power for WiFi on the different bands.

    If there are other networks on the same channel or on the neighbor
    channels, they will definitely interfere your connection. Try to use
    the most clear channel, check both ends (Pi and your device location).
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From bob prohaska@3:770/3 to Marco Moock on Fri Dec 10 21:37:45 2021
    Marco Moock <mo01@posteo.de> wrote:

    Is it the same power?

    Not sure I follow your question....

    The cellphone is definitely connecting to the same access point as
    the Pi, so the power seen by each would be the same, subject to the
    difference caused by a few feet displacement.

    Wavemon's "scan" command reports about 20 access points with mine
    registering 87%, of what I don't know, and all the rest below 70%.

    This is the relevant size, maybe they updated the database for max
    allowed power per country and this changed something.
    Be aware that need to check the local rules of your residence for the
    laws about max. power for WiFi on the different bands.

    The date command returns the correct timezone PST, locale reports
    en_US so I think the country is correct.


    If there are other networks on the same channel or on the neighbor
    channels, they will definitely interfere your connection. Try to use
    the most clear channel, check both ends (Pi and your device location).

    It looks like there are two other APs using channel 1, but they're
    both 20 dB down at the Pi4's end. My AP is an old D-Link DI524, it
    does not seem to have any diagnostics on the Web interface to check interference.

    I should perhaps reiterate that the problems emerged after a sudo
    apt update of the Pi4, I haven't done anything to the AP in years.

    Thanks for writing,

    bob prohaska

    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From Ralph Spitzner@3:770/3 to bob prohaska on Sat Dec 11 18:52:03 2021
    bob prohaska wrote on 12/10/21 2:54 AM:
    Following a RasPiOS upgrade yesterday, a Pi4 seems to be dropping
    its wifi connection considerably more than usual. In the past, this
    has been accompanied by signal strength readings below 70% on wavemon.
    Now, the signal strength is over 80% and the machine is still dropping
    the connection. Cellphones have no problem connecting.

    So far, the remedy seems to be turning wifi off and then back on. Are
    there any tricks that might help sort out what's wrong? There are many
    wifi networks visible to the Pi, but I think mine is the strongest.

    Thanks for reading,

    bob prohaska


    switch off wifi power management (iwconfig wlan0 power off)
    if that doesnt help, use okder firmware.
    Ihad to do both to stop loosing connection every n minutes....
    although I think power-management was the culprit.

    -rasp
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From bob prohaska@3:770/3 to Ralph Spitzner on Sun Dec 12 03:59:38 2021
    Ralph Spitzner <rasp@spitzner.org> wrote:
    bob prohaska wrote on 12/10/21 2:54 AM:
    Following a RasPiOS upgrade yesterday, a Pi4 seems to be dropping
    its wifi connection considerably more than usual. In the past, this
    has been accompanied by signal strength readings below 70% on wavemon.
    Now, the signal strength is over 80% and the machine is still dropping
    the connection. Cellphones have no problem connecting.

    So far, the remedy seems to be turning wifi off and then back on. Are
    there any tricks that might help sort out what's wrong? There are many
    wifi networks visible to the Pi, but I think mine is the strongest.

    Thanks for reading,

    bob prohaska


    switch off wifi power management (iwconfig wlan0 power off)
    if that doesnt help, use okder firmware.
    Ihad to do both to stop loosing connection every n minutes....
    although I think power-management was the culprit.


    Trying it now....

    Wouldn't power management interfere with all connections equally? There
    are usually about a dozen ssh connections open, typically only one or two
    drop. The rest stay up for days/weeks.

    Thanks for writing!

    bob prohaska
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From Jim Jackson@3:770/3 to bob prohaska on Sun Dec 12 19:44:20 2021
    On 2021-12-12, bob prohaska <bp@www.zefox.net> wrote:
    Ralph Spitzner <rasp@spitzner.org> wrote:
    bob prohaska wrote on 12/10/21 2:54 AM:
    Following a RasPiOS upgrade yesterday, a Pi4 seems to be dropping
    its wifi connection considerably more than usual. In the past, this
    has been accompanied by signal strength readings below 70% on wavemon.
    Now, the signal strength is over 80% and the machine is still dropping
    the connection. Cellphones have no problem connecting.

    So far, the remedy seems to be turning wifi off and then back on. Are
    there any tricks that might help sort out what's wrong? There are many
    wifi networks visible to the Pi, but I think mine is the strongest.

    Thanks for reading,

    bob prohaska


    switch off wifi power management (iwconfig wlan0 power off)
    if that doesnt help, use okder firmware.
    Ihad to do both to stop loosing connection every n minutes....
    although I think power-management was the culprit.


    Trying it now....

    Wouldn't power management interfere with all connections equally? There
    are usually about a dozen ssh connections open, typically only one or two drop. The rest stay up for days/weeks.

    Surely if you are saying you wifi connection goes down then ALL tcp/ip
    traffic over the wifi does down as well?

    Something does not sound right in the two desciptions of your problem
    given above
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From The Natural Philosopher@3:770/3 to Jim Jackson on Mon Dec 13 11:45:33 2021
    On 12/12/2021 19:44, Jim Jackson wrote:
    On 2021-12-12, bob prohaska <bp@www.zefox.net> wrote:


    Wouldn't power management interfere with all connections equally? There
    are usually about a dozen ssh connections open, typically only one or two
    drop. The rest stay up for days/weeks.

    Surely if you are saying you wifi connection goes down then ALL tcp/ip traffic over the wifi does down as well?

    Something does not sound right in the two desciptions of your problem
    given above

    I can have connections freeze and drop with wifi, but some stay up. In
    my case I am fairly sure the problem is the central heating boiler
    spark igniter, which throws broadband hash all over the place. I can ask
    the wifi to connect to another access point without losing TCP
    connections however, so *temporary* loss of the physical layer may or
    may not lead to a logical connection drop.

    Keepalives are not continuous things.

    --
    No Apple devices were knowingly used in the preparation of this post.

    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From bob prohaska@3:770/3 to Jim Jackson on Mon Dec 13 21:37:52 2021
    Jim Jackson <jj@franjam.org.uk> wrote:
    On 2021-12-12, bob prohaska <bp@www.zefox.net> wrote:
    Ralph Spitzner <rasp@spitzner.org> wrote:
    bob prohaska wrote on 12/10/21 2:54 AM:
    [snip]
    So far, the remedy seems to be turning wifi off and then back on. Are
    there any tricks that might help sort out what's wrong? There are many >>>> wifi networks visible to the Pi, but I think mine is the strongest.

    switch off wifi power management (iwconfig wlan0 power off)
    if that doesnt help, use okder firmware.
    Ihad to do both to stop loosing connection every n minutes....
    although I think power-management was the culprit.


    Trying it now....

    Out of six ssh sessions over wifi opened yesterday three are still up.


    Surely if you are saying you wifi connection goes down then ALL tcp/ip traffic over the wifi does down as well?

    Something does not sound right in the two desciptions of your problem
    given above

    I'm on a Pi4 running RasPiOS as I write this. The Pi4 is connected to my
    single WiFi access point. There are six ssh connections to other hosts,
    plus one ping session to the access point. Three of the ssh connections
    dropped overnight, the other three are still up. Ping times look normal
    for about the past twelve hours.

    Wavemon presently reports a signal level of -58dBm with a link quality
    of 73-74%. That's somewhat low, if I tilt the Pi just slightly it comes
    up to near 90%.

    One obvious question is where the disconnects originate: Wifi, router
    or remote (but still physically local) host. I don't know how to resolve
    that puzzle and was hoping to learn of some diagnostics that might help.
    The remote hosts are FreeBSD of various versions and vintages. I have also
    had difficulties with the Pi4 dropping its WiFi connection entirely, but
    that's what gets restored by turning WiFi off and back on. The ssh failures
    are more subtle.

    Thanks for reading,

    bob prohaska
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From Andy Burns@3:770/3 to bob prohaska on Mon Dec 13 21:52:34 2021
    bob prohaska wrote:

    The Pi4 is connected to my
    single WiFi access point. There are six ssh connections to other hosts,
    plus one ping session to the access point. Three of the ssh connections dropped overnight, the other three are still up.

    Is it possible some of the SSH sessions use keep-alives while the others do not?
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From Chris Green@3:770/3 to Andy Burns on Mon Dec 13 22:55:24 2021
    Andy Burns <usenet@andyburns.uk> wrote:
    bob prohaska wrote:

    The Pi4 is connected to my
    single WiFi access point. There are six ssh connections to other hosts, plus one ping session to the access point. Three of the ssh connections dropped overnight, the other three are still up.

    Is it possible some of the SSH sessions use keep-alives while the others do not?

    Also is it worth stepping up the ssh debugging by using -v, -vv or
    -vvv? That might tell you what ssh itself thinks is the reason for dropped connections.

    --
    Chris Green
    ·
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From bob prohaska@3:770/3 to Chris Green on Mon Dec 13 23:28:31 2021
    Chris Green <cl@isbd.net> wrote:
    Andy Burns <usenet@andyburns.uk> wrote:
    bob prohaska wrote:

    The Pi4 is connected to my
    single WiFi access point. There are six ssh connections to other hosts,
    plus one ping session to the access point. Three of the ssh connections
    dropped overnight, the other three are still up.

    Is it possible some of the SSH sessions use keep-alives while the others do not?

    Not sure. I haven't done anything beyond using ping to see if it keeps things up. Near as I can tell it doesn't help much, if at all. If what you mean by
    a keep-alive is different, please tell me what to check for.

    Also is it worth stepping up the ssh debugging by using -v, -vv or
    -vvv? That might tell you what ssh itself thinks is the reason for dropped connections.


    Yes! Can I simply use something like
    ssh -vv user@host ?
    Where will I find the extra output?

    As an aside, I brought all the ssh sessions back up several hours ago.
    They're all still up.....

    Thanks for writing!

    bob prohaska
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From Chris Green@3:770/3 to bob prohaska on Tue Dec 14 08:40:32 2021
    bob prohaska <bp@www.zefox.net> wrote:
    Chris Green <cl@isbd.net> wrote:
    Also is it worth stepping up the ssh debugging by using -v, -vv or
    -vvv? That might tell you what ssh itself thinks is the reason for dropped connections.


    Yes! Can I simply use something like
    ssh -vv user@host ?
    Where will I find the extra output?

    On standard output (or maybe standard error), ... thinks, I'll try it:-

    ssh -vvv backup 2>log

    Works beautifully! Loads of debug information is sent to 'log' while
    your connection works as usual.


    As an aside, I brought all the ssh sessions back up several hours ago. They're all still up.....

    Sort of sods law that isn't it! :-)

    --
    Chris Green
    ·
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From Jim Jackson@3:770/3 to bob prohaska on Tue Dec 14 11:13:04 2021
    On 2021-12-13, bob prohaska <bp@www.zefox.net> wrote:
    Chris Green <cl@isbd.net> wrote:
    Andy Burns <usenet@andyburns.uk> wrote:
    bob prohaska wrote:

    The Pi4 is connected to my
    single WiFi access point. There are six ssh connections to other hosts, >>> > plus one ping session to the access point. Three of the ssh connections >>> > dropped overnight, the other three are still up.

    Is it possible some of the SSH sessions use keep-alives while the others do not?

    Not sure. I haven't done anything beyond using ping to see if it keeps things up. Near as I can tell it doesn't help much, if at all. If what you mean by
    a keep-alive is different, please tell me what to check for.

    the ssh protocol allows for "keepalive" packets to be periodically sent
    between the ssh client and ssh server - this is neccessary because some
    NAT routers close tcp connections that have had no traffic for some
    period.

    Put

    ServerAliveInterval 60

    in your .ssh/config file

    see man ssh_config for the full details.


    Also is it worth stepping up the ssh debugging by using -v, -vv or
    -vvv? That might tell you what ssh itself thinks is the reason for dropped >> connections.


    Yes! Can I simply use something like
    ssh -vv user@host ?
    Where will I find the extra output?

    As an aside, I brought all the ssh sessions back up several hours ago. They're all still up.....

    Thanks for writing!

    bob prohaska

    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From bob prohaska@3:770/3 to Chris Green on Tue Dec 14 21:17:43 2021
    Chris Green <cl@isbd.net> wrote:
    bob prohaska <bp@www.zefox.net> wrote:
    Chris Green <cl@isbd.net> wrote:
    Also is it worth stepping up the ssh debugging by using -v, -vv or
    -vvv? That might tell you what ssh itself thinks is the reason for dropped >> > connections.


    Yes! Can I simply use something like
    ssh -vv user@host ?
    Where will I find the extra output?

    On standard output (or maybe standard error), ... thinks, I'll try it:-

    ssh -vvv backup 2>log

    Works beautifully! Loads of debug information is sent to 'log' while
    your connection works as usual.


    As an aside, I brought all the ssh sessions back up several hours ago.
    They're all still up.....

    Sort of sods law that isn't it! :-)

    Overnight two connections went down. The only message is of the form:

    packet_write_wait: Connection to 50.1.20.24 port 22: Broken pipe

    That's what I've been seeing all along, -v or no -v 8-)

    Can anybody hazard a guess which end initiated the disconnect?
    From the wording, it looks like the Pi discovered that the link
    was already gone, said so and exited.

    Thanks for reading,

    bob prohaska

    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From The Natural Philosopher@3:770/3 to bob prohaska on Wed Dec 15 07:48:19 2021
    On 14/12/2021 21:17, bob prohaska wrote:
    Overnight two connections went down. The only message is of the form:

    packet_write_wait: Connection to 50.1.20.24 port 22: Broken pipe

    That's what I've been seeing all along, -v or no -v8-)

    Can anybody hazard a guess which end initiated the disconnect?

    Mmm. Interesting philosophical concept, if I take an axe to a cable,
    please tell me which end of it 'initiated the disconnect'?



    From the wording, it looks like the Pi discovered that the link
    was already gone, said so and exited.


    That's better. The *link was already gone*.



    --
    “It is dangerous to be right in matters on which the established
    authorities are wrong.”

    ― Voltaire, The Age of Louis XIV

    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From Martin Gregorie@3:770/3 to bob prohaska on Wed Dec 15 08:24:20 2021
    On Tue, 14 Dec 2021 21:17:43 -0000 (UTC), bob prohaska wrote:


    Overnight two connections went down. The only message is of the form:

    packet_write_wait: Connection to 50.1.20.24 port 22: Broken pipe

    That's what I've been seeing all along, -v or no -v 8-)

    Can anybody hazard a guess which end initiated the disconnect?
    From the wording, it looks like the Pi discovered that the link was
    already gone, said so and exited.

    You can only know that if you're using 'keep alive' messages of some
    type, and SSH connections typically don't do that, unlike, say the now- obsolete X.25.

    IIRC X.25 was very telephone-like, with a central 'exchange' node, which regularly checked all open connections and, if one half of a connection
    died, both the initiator and the recipient of a connection got notified
    of the faiure.

    I think that equivalent checks for an SSH session have to be handled at application level: One end needs to send periodic test messages and
    report errors if it doesn't get a 'test received' response. The other end
    wound need to be expecting 'testing' messages and to report errors if
    they don't arrive when expected.

    HTH





    Thanks for reading,

    bob prohaska

    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From Anssi Saari@3:770/3 to bob prohaska on Wed Dec 15 11:29:32 2021
    bob prohaska <bp@www.zefox.net> writes:

    Overnight two connections went down. The only message is of the form:

    packet_write_wait: Connection to 50.1.20.24 port 22: Broken pipe

    That's what I've been seeing all along, -v or no -v 8-)

    So did you use -v or -vvv? And maybe use -E to specify the log file.

    Can anybody hazard a guess which end initiated the disconnect?

    ssh client in Debian (and so probably in Raspbian or whatsit now) sends
    TCP keepalives by default. If the connection to the other end is down
    then the ssh connection also goes down. You might try using
    -o 'TCPKeepAlive=no' with ssh to see if it helps.

    --- SoupGate-Win32 v1.05
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