You can optionally configure TCP keep-alive connections in the ase.conf file of ASE. Following is a snippet of ase.conf displaying the enable_sideband_keepalive variable. The default value is set to false.

; enable connection keepalive for requests from gateway to ase.
; This setting is applicable only in sideband mode.
; Once enabled ase will add 'Connection: keep-alive' header in response
; Once disabled ase will add 'Connection: close' header in response