Traceroute UDP or ICMP?

[morenuf]

I am having trouble doing TraceRoute through my router under OSX. After
months of frustration,finally OSX versions of TraceRoute did arrive that
allowed choice of UDP (default) or ICMP, and ICMP setting did finally
allow TraceRoute to work through my router.

Does a UDP port need to be open in my router configuration to allow UDP
Traceroute to run correctly under UDP & OSX? What port number is that?

I understand some people do have such problems through various routers.
I certainly am not an expert on network issues like this.

G4 450 & 933
both on OSX 10.2.4
MIH 130A XRouter Pro by MacSense (Xsense.com)

MacSense router works fine (including traceroute) under OS9.22 and
router works in OSX for everything but any Traceroute defaulting to UDP.



=======
For 4 months no TraceRoute program utility I found that would run under
OSX would work through my router under OSX.

After 4-5 months trying everything I could think of and nothing worked,
IPNetMonitor 1.2x and WhatRoute 1.814 versions finally came out and both
of these (although they both use UDP protocol by default) do have a
feature to use ICMP for TraceRoute and when set to ICMP, the TraceRoute
function finally does work.

Current and earlier versions of various shareware, free & commercial
traceroute OSX programs have not and do not currently work through my
router under OSX:

GlobalTraceRoute, NetBarrierX3's TraceRoute, and VisualRoute.



Thanks in advance for comments.
Morenuf

[Jeremy]

morenuf <morenuf@nobodyhome.com.invalid> wrote:

> I am having trouble doing TraceRoute through my router under OSX. After
> months of frustration,finally OSX versions of TraceRoute did arrive that
> allowed choice of UDP (default) or ICMP, and ICMP setting did finally
> allow TraceRoute to work through my router.
>
> Does a UDP port need to be open in my router configuration to allow UDP
> Traceroute to run correctly under UDP & OSX? What port number is that?

You would need to allow UDP *outbound* for UDP-based traceroute, but you
won't need to open anything inbound for UDP.

The actual port number is not defined. The way UDP traceroute works is to
attempt to send datagrams to an unused UDP port; that will be a high port,
but could be pretty much anything, and won't necessarily be the same every
time.

The responses from a UDP traceroute are ICMP error messages (either time
exceeded or port unreachable). That's what you would have to allow back
in through your firewall (despite common misconception, there is no real
reason to block all ICMP at a firewall, and there are good reasons not to).

If an ICMP-based traceroute works, just use that. It won't make any
difference in the diagnostic information you get back from it.

--
Jeremy | [email]jeremy@exit109.com[/email]