Command: set keepalive - stabilizing your connection to Nemesis

Description:
	With 'set keepalive on' (or variations) Nemesis sends some bytes
	to you every 3 minutes while you are being idle (that is to say:
	doing nothing). This can prevent losing your connection to Nemesis
	when you are idle if your internet service provider (ISP) causes
	this behaviour or if a NAT box is too oblivious (both see also in
	Note: below).

	If there are problems keeping your connection you can choose
	between some possibilities. The arguments' meanings are:

	on:	sends an invisible ANSI control sequence. This only works
		if ANSI settings are turned on (see also 'help ansi').
		For the Web Client https://nemesis.de/connect/client/ this
		is the best choice. Also 'set keepalive ansi' is supported.
	unix:	sends "<space><backspace>" which is suitable for xterm
		(X-Terminal) or compatible on Unix-like systems. There
		this sequence is invisible resp. the <space> is deleted.
	space:	sends a blank, a space.
	off:	turns keepalive off.
	Everything else sends the specified character(s).

Syntax:
	set keepalive on
	set keepalive ansi
	set keepalive unix
	set keepalive space
	set keepalive <characters>
	set keepalive off

Examples:
	set keepalive on
	set keepalive unix
	set keepalive space
	set keepalive blah

Note:
	It's perfectly acceptable to stay idle in Nemesis - even for
	extended periods of time.

	If the current interval of 3 minutes is too long for you, please
	don't hesitate and contact us! See also 'help admin'.
 
	The behaviour described above (losing connection while idle) can
	occur if your ISP uses Carrier-grade NAT or similar technology
	(see also https://en.wikipedia.org/wiki/Carrier-grade_NAT ). If
	the ISP has very limited IPv4 address space, they start to kill
	"idle" TCP sessions where nothing is transmitted. Sending a few
	bytes every few minutes bypasses this ;-)
	It also can happen if your Network Address Translation (NAT) box
	(see https://en.wikipedia.org/wiki/Network_address_translation )
	does not keep the TCP connections long enough.

	If there are disturbances on the way through the net between your
	computer and Nemesis, activated keepalive might cause loss of the
	connection. When data packets get lost on the way, the GameDriver
	(GD) recognises this and assumes the connection is dead and you
	will be disconnected.

	For more information regarding connecting to Nemesis (other ports
	than 2000, session encryption etc.) see 'help connect'.

	The keepalive feature was added by Kiri (see 'whois kiri' or
	https://nemesis.de/lpc/bin/finger/kiri ) in October 2017.

See also: helpdir/set, helpdir/unset, helpdir/ansi, helpdir/admin, helpdir/connect