FTP Timeout at 4 Hours On The Dot

[mlenco]

Hello

I setup 5 putty SSH session to 5 Cisco 3850 switches to push the new Denalli 16.3.7 to mitigate a memory leak issue on 16.3.6. At exactly 4 hours into the copy ftp: flash: the putty window closed with "Line Timeout Expired". 

Why did this happen? How do I prevent it so I can get back to FTPing the IOS?

I was sending from my Windows 7 Enterprise 64bit workstation via 3Cdaemon to a Cisco 3850 switch. 

[Mark Malone]

Could be a number of reasons why it broke , something in path causing it to drop , local pc issues , timers issues , firewalls etc
have you tried from another PC to rule out the local PC your on , the common theme there is they all use same system to FTP from ...
Or if your local try USB takes like 3 minutes to upload a file to flash
also try CRT instead of putty , try set the VTY timeout to be longer too on the switches if its set to default

4 hours to upload a IOS-XE file are you local or sending across a WAN ? thats very long time

[Jaderson Pessoa]

Hello

you can configure it using exec-timeout.

check it for more information: https://community.cisco.com/t5/wireless-and-mobility/to-increase-ssh-session-timeout/td-p/3098020