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The WhatRoute README Page

WhatRoute Version 1.4.3 - by Bryan Christianson

Whats New in Version 1.4.3 ?

Credits

What Does This Software Do

Hardware & Software Required

How Does WhatRoute Work

Problems in getting WhatRoute to work?

Setting WhatRoute Options

Credits
WhatRoute owes its existence to the work by Van Jacobsen, Steve Deering and others who invented the UNIX traceroute command.

The Metrowerks PowerPlant application framework is the basis of WhatRoute. Thanks guys, for taking all the hardwork out of Mac programming.

The WASTE engine used to display the results is the work Marco Piovanelli, Dan Crevier and Tim Paustian (who wrote the PowerPlant CWasteEdit class).

Fabrizio Oddone has been a major help in reporting/resolving problems. Thanks mate.

I am also extremely grateful for the all the feedback I've had on WhatRoute. I've tried to incorporate many of your ideas into the program and I'm always willing to hear your suggestions and criticisms. Thanks folks.


What does WhatRoute Do?

Trace Internet Paths
The program is designed to find the names of all the routers through which an IP packet passes on the way from your Macintosh to the destination host. In addition it measures the round-trip time from your Macintosh to the router thus enabling you to determine slow links (hops) in the Internet. It can also find dead links - ie routers that don't respond etc etc. If you have access to a UNIX machine you should read the man page that accompanies 'traceroute'.

PING Remote Hosts
WhatRoute will PING remote hosts. In this function a small packet is sent to a remote host and then the time taken for a reply to be received is recorded.

DNS Query
The DNS Query function is borrowed from the BIND software. The results of DNS Query show all the DNS Resource Records associated with an Internet host or domain. The explanation of this stuff is the beyond the scope of this document and for further information, I recommend the O'Reilly book, DNS and BIND.

Popup menus give you the choice of Query Class and Query Type. The different record types are discussed in detail in DNS and BIND

You can also query alternate servers to those specified in your TCP/IP control panel. This uses the BIND 4.9.5 resolver and is seperately configured in the DNS Options dialog. The setup is identical to that required on a UNIX system but is also very similar to the configuration in your Open Transport TCP/IP control panel.

DNS Query is the only function in WhatRoute that uses the BIND resolver. All other functions use the settings from your TCP/IP control panel.

Finger
WhatRoute includes a Finger client. This enables you to find information about users logged in to other hosts, providing that host is running a Finger server. A lot of system administrators consider this to be a security risk, so you may not find this command to be particularly useful.

To use the command, type user@host.somedomain.com in the text entry field.
To find all users on a host, type @host.somedomain.com in the text field.

Whois
This command enables you to find out about people, networks etc who are registered in the InterNic database.
The default server is rs.internic.net

To get a full list of instructions, clear the text entry field and click the Whois button. This will list the Help file from the Whois server running on rs.internic.net

If you wish to use an alternate server, type @host.somedomain.com after the Whois command

TELNET Server
WhatRoute can be configured as a TELNET server. This enables you to log into your Macintosh from a remote machine and execute traceroute, ping and dnsquery commands.

SelectingSettings|Telnet.. from the Menu bar, will bring up a dialog box that enables you to control access to the server.

You can completely disable the server, and also specify access control lists that permit or restrict hosts from connecting to the server. Further details on the access control lists is available by clicking the Help button on the dialog.

WhatRoute and Internet Config
If you have Internet Config installed, you can make WhatRoute a helper application for URLs with the format
traceroute://a.b.c/

An example of this usage is to be found in Bill Fishers InterMapper application.


Hardware/Software Requirements
1. OpenTransport 1.1 or later. WhatRoute does not work with MacTCP.
2. A network connection - Ethernet or PPP/SLIP
3. A Macintosh computer that uses Colour QuickDraw (68K or PowerPC)
4. System 7.5.3 or later. WhatRoute has been tested on beta releases of MacOS 8 and seems to be OK


Usage
Simply type an Internet host name or IP address in the field at the top of the screen. Press the return key or click the Trace button, and the window will display the names and IP addresses of all the routers between you and that host. WhatRoute tries each router 3 times and showsthe round trip time (in milliseconds) it takes for a packet to be sent to that router from your Macintosh and for a reply to be returned to you. If there is no reply from the remote host, WhatRoute will print an * instead of the time.

The other WhatRoute functions, Ping, Query, Finger Whos all use this same paradigm. Simply enter a host name and press the function button.


What If WhatRoute Doesn't Work ?
Do you have Open Transport installed?

Have you selected 'Open Transport' with 'Network Software Selector' ? - Classic Networking is not Open Transport.

If you are unable to get a response from any hosts on the 'net, you may wish to check with your ISP to see if they allow the use of this kind of utility. Some ISPs block the packet types generated and used by WhatRoute. (ICMP and UDP specifically)

Do any of your other network tools work ? eg Eudora, Netscape, etc etc

Please email me (bryanc@ihug.co.nz) if you are completely stumped.


OPTIONS
WhatRoute provides options that enable you some control over the operation. In most cases the defaults are satisfactory.

Maximum Hop Count The number of times to increment TTL until the host is declared to be unreachable.

Packet Size The size of the UDP data packet in bytes (including the IP and UDP headers) that WhatRoute sends.

UDP Port WhatRoute sends its first UDP probe to this port number when tracing routes. On successive probes, the port number is incremented. This enables WhatRoute to match replies from the remote hosts with the probes that were sent and then calculate the round trip time.
In general, you should probably not use other than the default value of 33435.

DNS Timeout The amount of time (in seonds) to spend waiting for response from the Domain Name Server. If this time expires, the host name is displayed as an IP address.

Trace/Ping Timeout The amount of time (in seconds) to wait for the ICMP response from the last traceprobe or ICMP echo request transmission. If a response is not received within this time, the probe/ping has failed.

Resolve Names By default, WhatRoute will translate IP addresses to names. If you wish to speed things up a bit, turn this option off and only IP addresses will be displayed.

Start With Clear Display If this option is set, the display pane will be cleared at the start of each trace.

Update Status Bar This currently does nothing. I thought people might want the option to turn off the clock and status bar. I guess I'll enable it if people want.

Beep on Completion This is one of those irritating things that people love or hate. Turn it off if you dont want your Mac to beep when it completes a trace.

Maximum Name Length This option specifies the field width for displaying host names. To turn the option off, give it a value of zero. The field defaults to a value of 32.


How does WhatRoute work ?
The idea is an extremely simple one, but it does rely on some knowledge of the kinds of data packets transmitted over the Internet. I suggest you read a book on TCP/IP theory to get a good understanding of the principles involved. However I will attempt to give a brief (but simplified and maybe partly fictional) description of the process.

Every IP packet on the Internet has a Time To Live (TTL) field in its header. As the packet passes through a router (the processors that connect networks together), the router decrements the TTL by one. When the value of the TTL reaches 0, the packet is 'dead' and is propogated no further. Normally, TTL is set to to a large value (such as 255) and the packet makes its way to the destination host.

In the traceroute algorithm (as implemented by WhatRoute) a UDP packet is sent with a TTL value of 1. This is the value displayed in the leftmost column on the output display. The first router the packet meets, decrements the TTL and says to itself "Uh oh - this packet just died" and sends an ICMP packet back to the source of the original packet - ie your Macintosh. WhatRoute receives this ICMP packet and retrieves the IP address of the router that sent the reply.

The IP address is then resolved back into its host name (with help from the Domain Name Server) and the hostname and IP address are displayed. Each hop is tried three times and the round trip time taken for that hop is displayed (in milliseconds). If there is no response from the router, WhatRoute displays the time as an '*'. If you see a lot of these, then you are traversing slow links.

After three tries, WhatRoute increments the TTL and tries again, finding new routers each time, and displaying the results as it does.

Eventually a packet will reach the destination host. Instead of replying with a 'Packet Died' message, the target host will respond with a 'Port not available' ICMP message. This message signals completion and WhatRoute reports Trace Complete.


Bug Fixes In version 1.4.3
WR 1.4.3 fixes a pretty badly broken 1.4.2

New features in version 1.4.2
Finger client
Whois client

Bug Fixes in WR 1.4.2
Time stamps extended to show 4 digit years
TELNET server re-written
Cancel button changed to Stop per Apple Human Interface Guidelines (Thanks Tog)

New features in version 1.4.1
Choice of DNS Servers when using the Query function. This uses code ported from BIND 4.9.5
Flood Ping - for those that must!!!
Settable UDP Port for traceroute probes
TELNET Server for using WhatRoute functions remotely
Updated to current releases of WASTE and CWASTEEdit
Miscellaneous enhancements and bug fixes.

New In Version 1.3.1
1. Fixed bug that caused WhatRoute to crash while Quitting
2. Added Option to display hostnames and addresses in a fixed length field in the Trace output.

New In Version 1.3
1. Added PING
2. Added DNS Query
3. Added the WASTE engine for displaying results
4. Added text hi-lighting

Fixed In Version 1.2.1
1. Fixed system crash when hitting the Cancel button.
2. Fixed error when opening endpoints on some models of Mac
3. Added internal DNS cache
4. Added OT Error codes to error messages.

New In Version 1.2
1. Printing - You can print the results of your trace
2. Save - You can save your results to a TEXT file
3. Remember the last 10 hosts you attempted to trace
4. Receive the GURL Apple event
5. Fixed source port of 0 bug.
6. Fixed trace timing problems (sometimes -ve times were displayed)
7. Better error reporting.
8. Other miscellaneous stuff

New In Version 1.1
1. The return key will activate the Trace button.
2. Esc or Command-. will activate the Cancel Button
3. Option settings are saved when you exit and restored when you next run the program.
4. The name of the last host pinged is restored when you start WhatRoute
5. The Set Packet Size Option now works
6. Other miscellaneous fixes and twiddles

Version 1.0
First Release


Please send comments, suggestions etc to: bryanc@ihug.co.nz

Bryan Christianson - August 1996