Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
NETSELECT(1)		    General Commands Manual		  NETSELECT(1)

       netselect - choose the fastest server automatically

       netselect  [-v|-vv|-vvv|-vvvv]  [-m  HOPS]  [-s	SERVERS]  [-t PACKETS]
       host ...

       netselect determines several facts about	all of the hosts given on  the
       command	line,  much faster than	you would if you manually tried	to use
       ping and	traceroute.

       For each	host, netselect	figures	out the	approximate ping time  (though
       not  as accurately as ping does), the number of network "hops" to reach
       the target, and the percentage of ping requests that got	 through  suc-
       cessfully.  Then	 netselect  calculates the "score" of each operational
       host based on these values.  A lower score is better,  in  the  end  it
       prints one line showing the server with the best	score.

       # netselect -vv \

       This is the output:	    2792 ms  23	hops  100% ok (	1/ 1) [	9213]    9999 ms  30	hops	0% ok		      94 ms   8	hops  100% ok (10/10) [	 169]		      46 ms  15	hops  100% ok (10/10) [	 115]	    9999 ms  30	hops	0% ok

       The  value in brackets is the "score" of	each operational host based on
       these values.  A	lower score is better.	The last line shows the	server
       with  the  best	score.	 If we had not used '-vv' on the command line,
       only this last line would have been printed.

       Note that for and  in  this
       case,  nothing got through at all.  That	indicates that either the host
       doesn't exist, or it is down.

       -v     Verbose  mode.   Displays	 nameserver  resolution	 messages   to
	      stderr.	You  probably  want  this  so that you don't get bored
	      waiting for a hundred name resolutions to	finish.

       -vv    Very verbose mode.  Displays nameserver resolution  and  statis-
	      tics (not	just scores) to	STDERR and STDOUT.

       -vvv   Very  very  verbose  mode.  Everything -vv prints, plus it print
	      every packet received as it happens.  Good for debugging or try-
	      ing to figure out	how it works.

       -vvvv  Very  very  very	verbose	 mode.	Everything -vvv	prints,	plus a
	      trace of all packets sent.

       -m HOPS
	      Maximum TTL (time	to live).  Don't accept	hosts that are further
	      than HOPS	away.

       -s SERVERS
	      Print  this  many	 "top-scoring" SERVERS at the end of the list.
	      If SERVERS is 0, then this disables printing of high scores.

       -t PACKETS
	      Make sure	at least 50% of	the hosts get tested  with  this  many
	      PACKETS.	 The  more  packets you	use, the more accurate are the
	      results... and the longer	it takes to run.  The default  is  10,
	      which is usually okay.

       -I     Use  ICMP	 instead of UDP	probes.	In some	occassions (firewalled
	      hosts) UDP probes	like those used	in traceroute  will  get  fil-
	      tered  out  and hosts might be perceived as dead.	Using this op-
	      tion will	make netselect use ICMP	probes instead.

       ping(8),	traceroute(8), netselect-apt(1).

       Avery Pennarun <>

DEBIAN				March 14, 2004			  NETSELECT(1)


Want to link to this manual page? Use this URL:

home | help