[Dxspider-support] Telnet connection keep alive

[Rene Olsen]

Hi.

Some home routers have settings that are not very friendly to low traffic connections.

Some of them have a timeout of just 5 minutes, and tears down the connection of there 
hasn't been a noticeble amount of trafic on the connection.

Not even a CR and a prompt back from spider, is enough traffic to maintain the connection 
open.

I have no idea why they do this. But since it is home routers, it is probably a question about 
money and ressources in the router.

I had a linksys router once, and with the default firmware I wasn't able to change the timeout 
setting, and it was just not able to maintain the connection to the cluser, when there was very 
low number of spots.

After an update to some third party firmware, I was able to change the timeout setting, and 
since then I didn't have any problems at all.

So in my opinion most diconnect issues, can be explained by the router in use.

And its not like the router tells both ends, that the connection has been closed. No, it just 
removes it from the NAT table and thats it.

Of course there is good and bad routers out there. I can only talk from my own experiences 
with home routers in the past.

Vy 73 de René / OZ1LQH

On 13 Nov 2016 at 17:39, jarmo via Dxspider-support wrote:

> Sun, 13 Nov 2016 13:23:18 +0000
> Dirk Koopman via Dxspider-support <dxspider-support at dxcluster.org>
> kirjoitti:
> 
> > 
> > It is rarely seen these days :-)
> 
> Not seen any :)
> > 
> > Any traffic, in either direction, will delay the prompt, but is there
> > is no traffic for $user_interval seconds on your link, then it will
> > send a command prompt. Set/ping for nodes serves roughly the same
> > purpose.
> Does spider think, that it has send spot, even it is filtered and does
> not send prompt?
> 
> When I have set filter, to reject those ego,please, 59, please spots
> and also rtty/data, I get quite small amount of spots. Early morning
> hours, there's less spots anyway.
> 
> Now, in this situation connection becomes "zombie" I see, I have
> connected, but nothing happens, when sending something to cluster and
> no prompt can be seen either. I have noticed, that my routers firewall
> blocks out for some reason this telnet connection. It seems, that my
> client (cqrlog) should send something, to keep connection alive... Or,
> like I did, I took my linux firewall in use and bridged router channel.
> There's some other users also seen this happen.
> 
> Jarmo
> 
> 
> > Dirk
> > 
> > On 13/11/16 03:59, jarmo via Dxspider-support wrote:
> > > Now have tested connection and noticed that it is my routers
> > > firewall, what makes connection as "zombie", when there is not
> > > much spots in early morning hours.
> > >
> > > I bridged my router channel and use my linux firewall and it seems,
> > > that connection does not drop into "zombie".
> > >
> > > Dirk, could you explain "$user_interval", is it just probe
> > > with no data and waiting "ACK" response? Or is it some kind of
> > > ping?
> > >
> > > Seems, that these router firewalls blocks quite roughly traffic :)
> > > So, may need some kind of data, to keep connection alive?
> > >
> > > Jarmo, oh1mrr
> > >
> > > _______________________________________________
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> > > Dxspider-support at dxcluster.org
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> > 
> > 
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