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AmigaOS 4.0 - About OS4 - Commands

TRACEROUTE Networking
Purpose: To display the route packets take to a network host.
Format: TRACEROUTE [-d | DEBUG] [-m | MAXTTL=<maxttl>] [-n | NUMERIC] [-p | PORT=<port number>] [-q | QUERIES=<num queries>]
[-r | DONTROUTE] [-s | SOURCE=<source>] [-t | TOS=<tos>]
[-v | VERBOSE] [-w | WAIT=<wait time>] <hostname> [<packet size>]
Template: -d=DEBUG/S, -m=MAXTTL/K/N, -n=NUMERIC/S, -p=PORT/K/N, -q=QUERIES/K/N, -r=DONTROUTE/S, -s=SOURCE/K, -t=TOS/K/N, -v=VERBOSE/S, -w=WAIT/K/N, HOST/A, PACKETSIZE/N
Path: C:traceroute
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. 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 a specified host.

The <hostname> argument is mandatory and can either be a destination host name or an IP address, all other arguments have default values. The default probe datagram length is 40 bytes, but this may be increased by specifying a <packet size> argument (length in bytes) after the destination host name. The other arguments are as follows:

-d | DEBUG Sets the SO_DEBUG option on the socket being used to enable socket level debugging.
-m | MAXTTL Sets 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).
-n | NUMERIC Displays hop addresses numerically rather than symbolically and numerically (saves a nameserver address-to-name lookup for each gateway found on the path).
-p | PORT Sets the base UDP port number used in probes (default is 33434). Traceroute hopes that nothing is listening on UDP ports base + 1 to base + nhops 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.
-q | QUERIES Sets the number of probes sent at each TTL setting. The default is 3.
-r | DONTROUTE Bypasses 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 routed)).
-s | SOURCE Uses the following IP address (which usually is given as an IP number, not a hostname) as the source address in outgoing probe packets. On multi-homed hosts (those 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.
-t | TOS Sets the '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).
-v | VERBOSE Verbose output. Received ICMP packets other than TIME_EXCEEDED and UNREACHABLEs are listed.
-w | WAIT Sets the time (in seconds) to wait for a response to a probe. The default is 5 secs.

TRACEROUTE 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 or MAXTTL argument). Three probes (change with -q or QUERIES argument) 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 or WAIT argument), a "*" is printed for that probe.

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 or PORT argument).

Example:

  3.OS4:> TRACEROUTE www.titan.co.nz
  traceroute to www.titan.co.nz (202.89.35.162), 30 hops max, 38 byte packets
   1 192.168.0.1 (192.168.0.1) 3.679 ms 0.798 ms 0.753 ms
   2 * * *
   3 202.89.36.34 (202.89.36.34) 53.739 ms 53.107 ms 53.446 ms
   4 fa0-0-1-21.cr01.ak11.maxnet.net.nz (202.89.36.17) 129.24 ms 189.616 ms 429.509 ms
   5 www.titan.co.nz (202.89.35.162) 51.134 ms 52.043 ms 51.963 ms


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Disclaimer: Amiga Auckland have prepared the above information for the use of its members based on our experiences and as such is subject to revision at any time. Amiga Auckland cannot guarantee any of the information and cannot be held accountable for any issues that may result from using it.


Copyright 2006 Amiga Auckland Inc. All rights reserved.
Revised: February 9, 2006.