ssh connection keepalive or idletimeout

[Tapas Mishra]

I have ssh access to a machine in my network,when I access it from
within the network and the connection lies idle for a lot of time the
connection does not die.
But when I login to the server from my home and there is no data
transmission for a long time the connection dies.
Here I would like to mention I have not set idletimeout or keepalive
in sshd_config and also the behavior of connection from inside network
and outside is different.
So what can be a reason for this?

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