CTRACE(1) User Contributed Perl Documentation CTRACE(1)NAMEctraceSYNOPSISctrace [options]
The only required option is -t target. The target may be specified as
a hostname or IPv4 address. Other valid execution modes are -W (web
traceroute gateway database update), and -l (list gateways).
DESCRIPTIONctrace is an IPv4 traceroute tool that supports many features missing
in standard 4.3BSD traceroute(8). It is programmed entirely in perl.
The primary difference between ctrace and other traceroute tools is its
ability to trace routes in multiple protocols. ctrace also has some
additional nifty features:
. Automatic round-trip-time (RTT) averaging, which makes output
cleaner and more intelligible.
. One or more packets can be launched per TTL/hop. By way of con‐
trast, 4.3BSD traceroute(8) forces at least two. This capability
makes ctrace faster.
. 4.3BSD traceroute(8) emulation option, so that ctrace will hook in
to existing parsers.
. The ability to skip an arbitrary number of hops, saving you time
that would be normally wasted tracerouting your own network.
. Fine-grained control over trace packet headers, assisting in
bypassing burdensome packet filters.
. Web-based traceroute gateway bounce support.
OPTIONS-a Disable RTT averaging mode. RTT averaging mode shows one "ms/avg."
RTT per hop instead of seeing a collection of 4.3BSD tracer‐
oute(8)-like "ms" RTT values. This option has no effect if -q is
set to 1.
-b siteid
Bounce mode. Uses the website siteid to run the traceroute,
returning the results transparently. Note that this feature is
still not as adaptable as hoped. Use -l to list known bounce
sites.
-c icmpcode
ICMP message code. An integer in the range 0-255 is expected. The
default value for this field is 0. This option affects ICMP traces
only (see -p option).
-d dstport
Destination port number. The default value is 53. A value of 0
means that destination ports will be generated at random. This
option affects TCP and UDP traces only (see -p option).
-f failhops
Failing failhops consecutive hops will cause the program to abort.
This is useful for preventing lengthy max-TTL timeout situations
where packet filters are blocking further progress. In mass-traces
of unknown networks, it drasitically improves speed. The default
value is 2.
-h Display command line help. This is also displayed if the -t argu‐
ment is ommitted.
-i icmptype
ICMP message type. An integer in the range 0-255 is expected. The
default value for this field is 8. This option affects ICMP traces
only (see -p option).
-j jumphops
Start on the jumphops'th hop (ie: initilise the TTL to jumphops).
This is useful for saving the time you waste mapping the first few
hops (you and your ISP's networks) thousands of times over. The
default is not to jump.
-l List the web traceroute gateways currently in the local database,
along with their siteid. Used with -b.
-m ttl
Max time to live (TTL). This is the maximum number of hops that
you want to make before giving up on reaching your target. The
default value is 35.
-n `Numeric mode'. In this mode, the program will not use DNS to
resolve host names. The output in this mode is supposed to be com‐
patible with 4.3BSD traceroute(8)'s -n mode.
-o `Oldschool mode'. ctrace will emulate 4.3BSD traceroute(8) output
almost perfectly. The only present differences from 4.3BSD tracer‐
oute(8) are that packet size is always reported as 40 bytes (irre‐
spective of the protocol and options selected), and that ctrace
will still allow -q of 1 (minimum 4.3BSD traceroute(8) is 2). Old‐
school mode negates -v and implies -a.
-p [protocol]
The protocol to conduct the trace with. Valid values are icmp, tcp
and udp. The default value is udp. More protocols will probably
be added in the future.
-q queries
The number of queries (packets) to send per hop. Packets are dis‐
patched one at a time, so increasing this number will slow down
yout trace. One seems to be sufficient for most cases, three is
the recommended maximum. The default value is one.
-s srcport
Source port number. The default value of 0 means that source ports
will be generated at random. This option affects TCP and UDP
traces only (see -p option).
-t target
This is the target host of your trace. It can either be specified
as a hostname, or an IPv4 address.
-v Verbose mode. Displays additional information on ctrace's status.
This feature is mainly used for debugging. This option is incom‐
patible with -o (oldschool) mode, and will be disabled if both are
specified.
-w secs
The time in seconds to wait for responses to packets before assum‐
ing that they will never come. The default value is 3.
-E Enables exit-reporting mode. A human-readable summary of the exit
condition will be printed to STDERR prior to program termination.
-M Enables 'mix mode'. In this mode, STDERR and STDOUT are combined
in to STDOUT. This is a parser-friendly mode, for traceroute
parsers such as ct2db (http://pratyeka.org/ct2db/).
-T Currently non-working flag intended for IP TOS specification.
-F⎪P⎪R⎪S⎪U⎪X⎪Y
Toggles the FIN,PSH,RST,SYN,URG and reserved (unused) flags in out‐
going TCP packets. These options only affect TCP traces (see -p
option). Only the STN flag is turned on by default.
-W Update the web traceroute gateway ('bounce site') database from
www.traceroute.org. Note that you are better off compiling a
sitelist manually, as many traceroute.org sites are either down or
do not cooperate with ctrace.
TYPES OF TRACES
ICMP (protocol 2)
Using the -i (ICMP type) and -c (ICMP code) switches, it is possi‐
ble to send a variety of ICMP-based traces. Due to the nature of
ICMP, most type/code combinations will not yield ICMP TTL expired
messages (the basis of traceroute), thus will not work. Other
types are either obsolete, or heavily filtered on modern routers
(will not pass a couple of hops at most). Known good values for
ICMP types and codes are; echo response (type 0, code 0), echo
request (type 8, code 0).
TCP (protocol 6)
Destination ports of 80 (HTTP), 21 (FTP), 25 (SMTP), 110 (POP3) are
probably good bets. If you cannot get through, altering TCP header
flags (-F⎪P⎪R⎪S⎪U⎪X⎪Y) may be helpful. Source ports of 53 (DNS)
and 20 (FTP) are often firewall 'special cases'.
UDP (protocol 17)
The classic UDP source and destination port is 53 (DNS), it is
rarely filtered.
Bounced
Using the -b option, it is possible to run a trace from a foreign
web traceroute gateway and return the results. Useful for topology
discovery.
URL
The latest version of the code can be found at
http://www.pratyeka.org/ctrace/
BUGS, SUGGESTIONS, ETC.
Send to the author. The current BUGS and TODO files are distributed
with the latest version of the code.
AUTHOR
Walter Stanish <walter@pratyeka.org>, based upon code by ShaD0w.
SEE ALSO
Related Code
ct2db (http://pratyeka.org/ct2db/).
Man Pages
Net::RawIP, pcap(3), traceroute(8).
RFCs
RFC791 Internet Protocol (IP), RFC792 Internet Control Message Pro‐
tocol (ICMP).
HISTORYctrace grew out of a couple of hacks to ShaD0w's Net::RawIP demonstra‐
tion traceroute script. For the full history, see the HISTORY file in
the distribution archive, also available on the ctrace website.
3rd Berkeley Distribution perl v5.6.1 CTRACE(1)
