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Re: [LUG] [External] Re: Continual network problems on Fedora 31

 

Some general pointers from reading this...

Firstly, I don't have much experience of Fedora, I'm an Arch Linux guy, so there may 
be some comments here that just don't apply... 😊

Secondly, I notice that a live OS seemed to work ok? That would imply that it's the 
*OS*, not the hardware (computer + network)... so... you *might* be chasing a 
ghost... maybe 😉

Anyway, as you're already doing... keeping a log of what's happening is best. 
Doesn't matter if it's a text file (best) or paper, but... 

What time does it happen
What's the status of the links when there was communication and no communication, by 
this I mean:

ip link         - what's up / down
ip addr                 - what's the addresses on each link (a single network 
adapter could have more than 1 IPv4 address and can have more than one IPv6 address 
...)
ethtool <adapter name>  - is it connected correctly (i.e. 100Mb / Full Duplex ... 
10Mb/Half.. 1Gb ... etc...)

continuous ping on both interfaces might actually cause interfaces to start up (i.e. 
wifi), but worth using... but... when the link changes, try pinging by name AND ip 
address - i.e. 

ping 208.67.222.222
ping resolver1.opendns.com

(or your choice...)

Same with your router, if it has a name...?

Do you have more than one network management service running - systemd can be 
interfering with NetworkManager and DNS and timesync and... and... and...

Also worth checking is your local computer's health at the time... maybe use nmon to 
watch cpu and disk... or maybe nload to watch the network load

But... if it's happening fairly frequently, I'd try running a live OS (unless you 
want to do an upgrade anyway 😊) and just see if that magically cures the problem. At 
least you'll know if it's the local computer. Then it's your choice to dive in, or 
wipe away 😉



-----Original Message-----
From: list <list-bounces@xxxxxxxxxxxxx> On Behalf Of Sebastian
Sent: 01 February 2021 17:53
To: Peter Walker <peter.walker@xxxxxxxxxxxxxxx>
Subject: [External] Re: [LUG] Continual network problems on Fedora 31

Dear Peter,

> If there is another machine on the network with a static IP set the 
> same as yours that would not show. However if it is up you could try 
> pinging it using the other interface (ie. switch off wireless then 
> ping the wireless IP over the wired connection) nothing should answer.

The ping shows a "Destination Host Unreachable" error when done from both interfaces 
to the other (disconnected) interface, which does seem to indicate that there isn't 
another PC trying to use my IP addresses.

> As I said I think this is unlikely as the problem would be unlikely to 
> disappear so quickly if this was the case.

Certainly - the PCs on this network are generally connected early in the day and 
left on until the evening, so there's very little likelihood of random collisions, 
that is unless the Windows machines are reconnecting more frequently by themselves.

> I was confused by your ip addr output as you have 2 IPv4 addresses for 
> the ethernet. Not in itself an issue but not sure where the second 
> came from. I assume the 192.168.1.107 is the address you are using?

It seems as though 192.168.1.107 is for the Ethernet, and 192.168.1.99 is for the 
wireless interface. The 192.168.1.71 (Ethernet) address is listed with a prefix 
length of 32 instead of the usual 24; maybe this is the difference? As for the 
wireless interface, I can only see one IP address so maybe there were only three in 
total.

Thanks for your continuing help :)

Best wishes,

Sebastian

--
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- Matrix: '@seabass:chat.weho.st'

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