1.\"	$KAME: traceroute6.8,v 1.10 2004/06/06 12:35:15 suz Exp $
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30.Dd November 25, 2020
31.Dt TRACEROUTE6 8
32.Os
33.\"
34.Sh NAME
35.Nm traceroute6
36.Nd "print the route IPv6 packets will take to a network node"
37.\"
38.Sh SYNOPSIS
39.Nm
40.Bk -words
41.Op Fl adIlnNrSTUv
42.Ek
43.Bk -words
44.Op Fl f Ar firsthop
45.Ek
46.Bk -words
47.Op Fl g Ar gateway
48.Ek
49.Bk -words
50.Op Fl m Ar hoplimit
51.Ek
52.Bk -words
53.Op Fl p Ar port
54.Ek
55.Bk -words
56.Op Fl q Ar probes
57.Ek
58.Bk -words
59.Op Fl s Ar src
60.Ek
61.Bk -words
62.Op Fl t Ar tclass
63.Ek
64.Bk -words
65.Op Fl w Ar waittime
66.Ek
67.Bk -words
68.Op Fl A Ar as_server
69.Ek
70.Bk -words
71.Ar target
72.Op Ar datalen
73.Ek
74.\"
75.Sh DESCRIPTION
76The
77.Nm
78utility
79uses the IPv6 protocol hop limit field to elicit an ICMPv6 TIME_EXCEEDED
80response from each gateway along the path to some host.
81.Pp
82The only mandatory parameter is the destination host name or IPv6 address.
83The default probe datagram carries 20 bytes of payload,
84in addition to the IPv6 header.
85The size of the payload can be specified by giving a length
86(in bytes)
87after the destination host name.
88.Pp
89Other options are:
90.Bl -tag -width Ds
91.It Fl a
92Turn on AS# lookups for each hop encountered.
93.It Fl A Ar as_server
94Turn on AS# lookups and use the given server instead of the default.
95.It Fl d
96Debug mode.
97.It Fl f Ar firsthop
98Specify how many hops to skip in trace.
99.It Fl g Ar gateway
100Specify intermediate gateway.
101Please note that
102.Nm
103tries to use routing headers.
104.It Fl I
105Use ICMP6 ECHO instead of UDP datagrams.
106.It Fl l
107Print both host hostnames and numeric addresses.
108Normally
109.Nm
110prints only hostnames if
111.Fl n
112is not specified, and only numeric addresses if
113.Fl n
114is specified.
115.It Fl m Ar hoplimit
116Specify maximum hoplimit, up to 255.
117The default is the value of the
118.Va net.inet6.ip6.hlim
119.Xr sysctl 8
120(the same default used for TCP connections).
121.It Fl n
122Do not resolve numeric address to hostname.
123.It Fl N
124Use a packet with no upper layer header for the probes,
125instead of UDP datagrams.
126.It Fl p Ar port
127Set SCTP/TCP/UDP port number to
128.Ar port .
129.It Fl q Ar probes
130Set the number of probe per hop count to
131.Ar probes .
132.It Fl r
133Bypass the normal routing tables and send directly to a host
134on an attached network.
135If the host is not on a directly-connected network,
136an error is returned.
137This option corresponds to the
138.Dv SO_DONTROUTE
139socket option;
140it can be used to ping a local host through an interface
141that has no route through it
142(e.g., after the interface was dropped by a routing daemon).
143.It Fl s Ar src
144.Ar Src
145specifies the source IPv6 address to be used.
146.It Fl S
147Use SCTP packets for the probes.
148The size of probe packets must be a multiple of 4.
149If
150.Ar datalen
151is up to 28, probe packets consist of a SHUTDOWN-ACK chunk possibly bundled
152with a PAD chunk.
153For larger probe packets, an INIT chunk is used.
154.It Fl t Ar tclass
155.Ar tclass
156specifies the
157.Em traffic class
158used when sending probe packets.
159The value must be a decimal integer in the range 0 to 255.
160The default is 0.
161.It Fl T
162Use TCP segments for the probes.
163.It Fl U
164Use UDP datagrams for the probes.
165This is the default.
166.It Fl v
167Be verbose.
168.It Fl w Ar waittime
169Specify the delay time between probes.
170.El
171.Pp
172This program prints the route to the given destination and the round-trip
173time to each gateway, in the same manner as traceroute.
174.Pp
175Here is a list of possible annotations after the round-trip time for each gateway:
176.Bl -hang -offset indent
177.It !N
178Destination Unreachable - No Route to Host.
179.It !P
180Destination Unreachable - Administratively Prohibited.
181.It !S
182Destination Unreachable - Not a Neighbour.
183.It !A
184Destination Unreachable - Address Unreachable.
185.It !H
186Parameter Problem - Unrecognized Next Header Type.
187.It !\&
188This is printed if the hop limit is <= 1 on a port unreachable message.
189This means that the packet got to the destination,
190but that the reply had a hop limit that was just large enough to
191allow it to get back to the source of the traceroute6.
192This was more interesting in the IPv4 case,
193where some IP stack bugs could be identified by this behaviour.
194.El
195.\"
196.Sh EXIT STATUS
197The
198.Nm
199utility will exit with 0 on success, and non-zero on errors.
200.\"
201.Sh SEE ALSO
202.Xr ping 8 ,
203.Xr traceroute 8
204.\"
205.Sh HISTORY
206The
207.Nm
208utility first appeared in WIDE hydrangea IPv6 protocol stack kit.
209