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TRACEROUTE6(8)		    System Manager's Manual		TRACEROUTE6(8)

NAME
       traceroute6 -- print the	route IPv6 packets will	take to	a network node

SYNOPSIS
       traceroute6  [-adEIlnNrSTUv]  [-f  firsthop] [-g	gateway] [-m hoplimit]
		   [-p port] [-q probes] [-s src] [-t  tclass]	[-w  waittime]
		   [-A as_server] target [datalen]

DESCRIPTION
       The  traceroute6	 utility  uses	the  IPv6  protocol hop	limit field to
       elicit an ICMPv6	TIME_EXCEEDED response from  each  gateway  along  the
       path to some host.

       The  only  mandatory parameter is the destination host name or IPv6 ad-
       dress.  The default probe datagram carries 20 bytes of payload, in  ad-
       dition to the IPv6 header.  The size of the payload can be specified by
       giving a	length (in bytes) after	the destination	host name.

       Other options are:

       -a      Turn on AS# lookups for each hop	encountered.

       -A as_server
	       Turn on AS# lookups and use the given server instead of the de-
	       fault.

       -d      Debug mode.

       -E      Detect  ECN bleaching.  Set the IPTOS_ECN_ECT1 Explicit Conges-
	       tion Notification (ECN) bits (01), and report if	 the  hop  has
	       bleached	 (00)  or  mangled (10)	them, or if it is experiencing
	       congestion (11).	 Otherwise, report that	it passed the bits ap-
	       propriately.  If	-t is also specified,  the  corresponding  ECN
	       bits will be replaced.

       -f firsthop
	       Specify how many	hops to	skip in	trace.

       -g gateway
	       Specify	intermediate  gateway.	 Please	 note that traceroute6
	       tries to	use routing headers.

       -I      Use ICMP6 ECHO instead of UDP datagrams.

       -l      Print both host	hostnames  and	numeric	 addresses.   Normally
	       traceroute6  prints  only hostnames if -n is not	specified, and
	       only numeric addresses if -n is specified.

       -m hoplimit
	       Specify maximum hoplimit, up to 255.  The default is the	 value
	       of  the net.inet6.ip6.hlim sysctl(8) (the same default used for
	       TCP connections).

       -n      Do not resolve numeric address to hostname.

       -N      Use a packet with no upper layer	header for the probes, instead
	       of UDP datagrams.

       -p port
	       Set SCTP/TCP/UDP	port number to port.

       -q probes
	       Set the number of probe per hop count to	probes.

       -r      Bypass the normal routing tables	and send directly to a host on
	       an attached network.  If	the host is  not  on  a	 directly-con-
	       nected  network,	an error is returned.  This option corresponds
	       to the SO_DONTROUTE socket option; it can be used to ping a lo-
	       cal host	through	an interface that  has	no  route  through  it
	       (e.g., after the	interface was dropped by a routing daemon).

       -s src  Src specifies the source	IPv6 address to	be used.

       -S      Use  SCTP  packets  for	the probes.  The size of probe packets
	       must be a multiple of 4.	 If datalen is up to 28, probe packets
	       consist of a SHUTDOWN-ACK chunk possibly	 bundled  with	a  PAD
	       chunk.  For larger probe	packets, an INIT chunk is used.

       -t tclass
	       tclass  specifies  the  traffic	class  used when sending probe
	       packets.	 The value must	be a decimal integer in	the range 0 to
	       255.  The default is 0.

       -T      Use TCP segments	for the	probes.

       -U      Use UDP datagrams for the probes.  This is the default.

       -v      Be verbose.

       -w waittime
	       Specify the delay time between probes.

       This program prints the route to	the given destination and  the	round-
       trip time to each gateway, in the same manner as	traceroute.

       Here  is	 a  list of possible annotations after the round-trip time for
       each gateway:

	     !N	     Destination Unreachable - No Route	to Host.

	     !P	     Destination Unreachable - Administratively	Prohibited.

	     !S	     Destination Unreachable - Not a Neighbour.

	     !A	     Destination Unreachable - Address Unreachable.

	     !H	     Parameter Problem - Unrecognized Next Header Type.

	     !	     This is printed if	the hop	limit is <= 1 on  a  port  un-
		     reachable message.	 This means that the packet got	to the
		     destination,  but that the	reply had a hop	limit that was
		     just large	enough to allow	it to get back to  the	source
		     of	 the  traceroute6.   This  was more interesting	in the
		     IPv4 case,	where some IP stack bugs could	be  identified
		     by	this behaviour.

EXIT STATUS
       The  traceroute6	 utility  will exit with 0 on success, and non-zero on
       errors.

SEE ALSO
       ping(8),	traceroute(8)

HISTORY
       The traceroute6 utility first appeared in WIDE hydrangea	IPv6  protocol
       stack kit.

FreeBSD	14.3		       October 25, 2023			TRACEROUTE6(8)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=traceroute6&manpath=FreeBSD+14.3-RELEASE+and+Ports>

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