Subject: Re: Traceroute difficulties
To: Matthew Fincham <>
From: Dave Huang <>
List: netbsd-users
Date: 01/09/2003 02:37:41
On Thu, Jan 09, 2003 at 10:19:55AM +0200, Matthew Fincham wrote:
> I have a Windows system which is able to do the traceroute - but maybe it is
> using ICMP??

Yes, Windows tracert uses ICMP, and as far as I know, there's no way to
get it to use UDP.

> What I am trying to solve is actually a bit more than just getting
> traceroute to work. I am trying to use sendmail/mail to send mail to a mail
> server. The mail's are not getting through though. A look at the mailq
> indicates it is because there was no route to the host. And yet I can ping
> the host. So I though if I can sovle the traceroute problem, I can solve the
> mail problem. Another clue is that I can successfully send mail to my
> "local" mail server.

Hmm... if you can ping it, there must be a route to it... the only thing
I can think of is that the other end is sending back ICMP destination
unreachable when you try to connect to port 25. However, that doesn't
make sense if it's a mail server... What happens if you try to
 telnet mailserver 25

And I guess it's only one mail server you're having troubles with? You
don't have any trouble connecting to other servers?