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diff --git a/contrib/traceroute/traceroute.8 b/contrib/traceroute/traceroute.8 new file mode 100644 index 0000000..031ca47 --- /dev/null +++ b/contrib/traceroute/traceroute.8 @@ -0,0 +1,298 @@ +.\" Copyright (c) 1989, 1995, 1996 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms are permitted +.\" provided that the above copyright notice and this paragraph are +.\" duplicated in all such forms and that any documentation, +.\" advertising materials, and other materials related to such +.\" distribution and use acknowledge that the software was developed +.\" by the University of California, Berkeley. The name of the +.\" University may not be used to endorse or promote products derived +.\" from this software without specific prior written permission. +.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR +.\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED +.\" WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. +.\" +.\" $Header: traceroute.8,v 1.7 96/09/27 20:02:41 leres Exp $ +.\" +.TH TRACEROUTE 8 "27 September 1996" +.UC 6 +.SH NAME +traceroute \- print the route packets take to network host +.SH SYNOPSIS +.. while ((op = getopt(argc, argv, "dnrvg:m:p:q:s:t:w:")) != EOF) +.na +.B traceroute +[ +.B \-dnrv +] [ +.B \-g +.I gw_host +] [ +.B \-m +max_ttl +.I ] +.br +.ti +8 +[ +.B \-p +.I port +] [ +.B \-q +.I nqueries +] [ +.B \-s +.I src_addr +] +.br +.ti +8 +[ +.B \-t +.I tos +] [ +.B \-w +.I waittime +] +.I host +[ +.I packetlen +] +.ad +.SH DESCRIPTION +The Internet is a large and complex aggregation of +network hardware, connected together by gateways. +Tracking the route one's packets follow (or finding the miscreant +gateway that's discarding your packets) can be difficult. +.I Traceroute +utilizes the IP protocol `time to live' field and attempts to elicit an +ICMP TIME_EXCEEDED response from each gateway along the path to some +host. +.PP +The only mandatory parameter is the destination host name or IP number. +The default probe datagram length is 40 bytes, but this may be increased +by specifying a packet length (in bytes) after the destination host +name. +.PP +Other options are: +.TP +.B \-g +Specify a loose source route gateway (8 maximum). +.TP +.B \-m +Set the max time-to-live (max number of hops) used in outgoing probe +packets. The default is 30 hops (the same default used for TCP +connections). +.TP +.B \-n +Print hop addresses numerically rather than symbolically and numerically +(saves a nameserver address-to-name lookup for each gateway found on the +path). +.TP +.B \-p +Set the base UDP port number used in probes (default is 33434). +Traceroute hopes that nothing is listening on UDP ports +.I base +to +.I base + nhops - 1 +at the destination host (so an ICMP PORT_UNREACHABLE message will +be returned to terminate the route tracing). If something is +listening on a port in the default range, this option can be used +to pick an unused port range. +.TP +.B \-r +Bypass the normal routing tables and send directly to a host on an attached +network. +If the host is not on a directly-attached network, +an error is returned. +This option can be used to ping a local host through an interface +that has no route through it (e.g., after the interface was dropped by +.IR routed (8C)). +.TP +.B \-s +Use the following IP address (which must be given as an IP number, not +a hostname) as the source address in outgoing probe packets. On +hosts with more than one IP address, this option can be used to +force the source address to be something other than the IP address +of the interface the probe packet is sent on. If the IP address +is not one of this machine's interface addresses, an error is +returned and nothing is sent. +.TP +.B \-t +Set the +.I type-of-service +in probe packets to the following value (default zero). The value must be +a decimal integer in the range 0 to 255. This option can be used to +see if different types-of-service result in different paths. (If you +are not running 4.4bsd, this may be academic since the normal network +services like telnet and ftp don't let you control the TOS). +Not all values of TOS are legal or +meaningful \- see the IP spec for definitions. Useful values are +probably `-t 16' (low delay) and `-t 8' (high throughput). +.TP +.B \-v +Verbose output. Received ICMP packets other than TIME_EXCEEDED and +UNREACHABLEs are listed. +.TP +.B \-w +Set the time (in seconds) to wait for a response to a probe (default 5 +sec.). +.PP +This program attempts to trace the route an IP packet would follow to some +internet host by launching UDP probe +packets with a small ttl (time to live) then listening for an +ICMP "time exceeded" reply from a gateway. We start our probes +with a ttl of one and increase by one until we get an ICMP "port +unreachable" (which means we got to "host") or hit a max (which +defaults to 30 hops & can be changed with the \-m flag). Three +probes (change with \-q flag) are sent at each ttl setting and a +line is printed showing the ttl, address of the gateway and +round trip time of each probe. If the probe answers come from +different gateways, the address of each responding system will +be printed. If there is no response within a 5 sec. timeout +interval (changed with the \-w flag), a "*" is printed for that +probe. +.PP +We don't want the destination +host to process the UDP probe packets so the destination port is set to an +unlikely value (if some clod on the destination is using that +value, it can be changed with the \-p flag). +.PP +A sample use and output might be: + +.RS +.nf +[yak 71]% traceroute nis.nsf.net. +traceroute to nis.nsf.net (35.1.1.48), 30 hops max, 38 byte packet + 1 helios.ee.lbl.gov (128.3.112.1) 19 ms 19 ms 0 ms + 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms + 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms + 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 39 ms + 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 39 ms 39 ms 39 ms + 6 128.32.197.4 (128.32.197.4) 40 ms 59 ms 59 ms + 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 59 ms + 8 129.140.70.13 (129.140.70.13) 99 ms 99 ms 80 ms + 9 129.140.71.6 (129.140.71.6) 139 ms 239 ms 319 ms +10 129.140.81.7 (129.140.81.7) 220 ms 199 ms 199 ms +11 nic.merit.edu (35.1.1.48) 239 ms 239 ms 239 ms +.fi +.RE + +Note that lines 2 & 3 are the same. This is due to a buggy +kernel on the 2nd hop system \- lbl-csam.arpa \- that forwards +packets with a zero ttl (a bug in the distributed version +of 4.3BSD). Note that you have to guess what path +the packets are taking cross-country since the NSFNet (129.140) +doesn't supply address-to-name translations for its NSSes. +.PP +A more interesting example is: + +.RS +.nf +[yak 72]% traceroute allspice.lcs.mit.edu. +traceroute to allspice.lcs.mit.edu (18.26.0.115), 30 hops max + 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms + 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 19 ms 19 ms + 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 19 ms + 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 19 ms 39 ms 39 ms + 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 20 ms 39 ms 39 ms + 6 128.32.197.4 (128.32.197.4) 59 ms 119 ms 39 ms + 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 39 ms + 8 129.140.70.13 (129.140.70.13) 80 ms 79 ms 99 ms + 9 129.140.71.6 (129.140.71.6) 139 ms 139 ms 159 ms +10 129.140.81.7 (129.140.81.7) 199 ms 180 ms 300 ms +11 129.140.72.17 (129.140.72.17) 300 ms 239 ms 239 ms +12 * * * +13 128.121.54.72 (128.121.54.72) 259 ms 499 ms 279 ms +14 * * * +15 * * * +16 * * * +17 * * * +18 ALLSPICE.LCS.MIT.EDU (18.26.0.115) 339 ms 279 ms 279 ms +.fi +.RE + +Note that the gateways 12, 14, 15, 16 & 17 hops away +either don't send ICMP "time exceeded" messages or send them +with a ttl too small to reach us. 14 \- 17 are running the +MIT C Gateway code that doesn't send "time exceeded"s. God +only knows what's going on with 12. +.PP +The silent gateway 12 in the above may be the result of a bug in +the 4.[23]BSD network code (and its derivatives): 4.x (x <= 3) +sends an unreachable message using whatever ttl remains in the +original datagram. Since, for gateways, the remaining ttl is +zero, the ICMP "time exceeded" is guaranteed to not make it back +to us. The behavior of this bug is slightly more interesting +when it appears on the destination system: + +.RS +.nf + 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms + 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 39 ms + 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 39 ms 19 ms + 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 19 ms + 5 ccn-nerif35.Berkeley.EDU (128.32.168.35) 39 ms 39 ms 39 ms + 6 csgw.Berkeley.EDU (128.32.133.254) 39 ms 59 ms 39 ms + 7 * * * + 8 * * * + 9 * * * +10 * * * +11 * * * +12 * * * +13 rip.Berkeley.EDU (128.32.131.22) 59 ms ! 39 ms ! 39 ms ! +.fi +.RE + +Notice that there are 12 "gateways" (13 is the final +destination) and exactly the last half of them are "missing". +What's really happening is that rip (a Sun-3 running Sun OS3.5) +is using the ttl from our arriving datagram as the ttl in its +ICMP reply. So, the reply will time out on the return path +(with no notice sent to anyone since ICMP's aren't sent for +ICMP's) until we probe with a ttl that's at least twice the path +length. I.e., rip is really only 7 hops away. A reply that +returns with a ttl of 1 is a clue this problem exists. +Traceroute prints a "!" after the time if the ttl is <= 1. +Since vendors ship a lot of obsolete (DEC's Ultrix, Sun 3.x) or +non-standard (HPUX) software, expect to see this problem +frequently and/or take care picking the target host of your +probes. + +Other possible annotations after the time are +.BR !H , +.BR !N , +or +.B !P +(got a host, network or protocol unreachable, respectively), +.B !S +or +.B !F +(source route failed or fragmentation needed \- neither of these should +ever occur and the associated gateway is busted if you see one), +.B !X +(communication administratively prohibited), or +.B !<N> +(ICMP unreachable code N). +If almost all the probes result in some kind of unreachable, traceroute +will give up and exit. +.PP +This program is intended for use in network testing, measurement +and management. +It should be used primarily for manual fault isolation. +Because of the load it could impose on the network, it is unwise to use +.I traceroute +during normal operations or from automated scripts. +.SH SEE ALSO +netstat(1), ping(8) +.SH AUTHOR +Implemented by Van Jacobson from a suggestion by Steve Deering. Debugged +by a cast of thousands with particularly cogent suggestions or fixes from +C. Philip Wood, Tim Seaver and Ken Adelman. +.LP +The current version is available via anonymous ftp: +.LP +.RS +.I ftp://ftp.ee.lbl.gov/traceroute.tar.Z +.RE +.SH BUGS +Please send bug reports to traceroute@ee.lbl.gov. |
