Re: new wifi connection = nntp timeout = Emacs restart?

[Eric Abrahamsen <eric@ericabrahamsen.net>]

Robert Pluim <rpluim@gmail.com> writes:

>>>>>> On Mon, 04 May 2020 16:51:53 +0200, Lars Ingebrigtsen
> <larsi@gnus.org> said:
>
>     Lars> Robert Pluim <rpluim@gmail.com> writes:
>     >> Also, I see this when coming out of sleep and connecting to the same
>     >> wifi network, with the same IP, and the same DNS server, which I guess
>     >> implicates Emacs more.
>
>     Lars> It's unlikely to be something on your machine that's the
>     Lars> problem. It's
>     Lars> unfortunately common for routers/firewalls to eject the
>     Lars> apparently dead
>     Lars> connection from their routing tables, and when a new packet arrives
>     Lars> on that connection, it'll just discard it (instead of sending a RST
>     Lars> packet to you).  The result is a hanging connection.
>
> And no doubt they'll have some crappy justification for doing
> it. <sigh>
>
>     Lars> In my experience, this is quite common for the NAT routers
>     Lars> ISPs use in
>     Lars> front of your home, and less common for the firewalls that's close to
>     Lars> the server.
>
> Iʼve just sledgehammered in tcp-keepalives at 1 second intervals into
> make-network-process, and that at least makes the detection of the
> failed connection fast.
>
> Eric, are you on GNU/Linux? I can cook up a patch for that platform to
> try if you want.

Yes, I'm on arch linux. I'd be happy to try this out. I'll be switching
networks later this morning, if you've got something on hand already!

Robert Pluim <rpluim@gmail.com> writes:

>>>>>> On Mon, 04 May 2020 08:38:00 -0700, Eric Abrahamsen
> <eric@ericabrahamsen.net> said:
>     >> Iʼd rather you didnʼt move in that direction. 'make-network-process'
>     >> is low-level plumbing, 'open-network-stream' is what user code should
>     >> be using. What feature is 'open-network-stream' missing for you?
>
>     Eric> Sorry, that was a very poorly-written sentence. What I meant was that
>     Eric> `open-network-stream' *does* use `make-network-process'
>     Eric> internally, and
>     Eric> the hang is happening inside C code, not Lisp code. That was
>     Eric> all I was
>     Eric> trying to say.
>
> OK, had me worried for a second there :-)
>
>     >> Also, I see this when coming out of sleep and connecting to the same
>     >> wifi network, with the same IP, and the same DNS server, which I guess
>     >> implicates Emacs more.
>
>     Eric> I really don't know very much about networking,
>     Eric> unfortunately. I'm just
>     Eric> trying to provide debugging data, possibly leads, baseless
>     Eric> speculation,
>     Eric> and red herrings.
>
> Once upon a time, IP networking was relatively simple, but those days
> are gone now. Red herrings I suspect Iʼd be partial to, Iʼve never
> tried those :-)

When pickled, they're not bad.