> On Thu, Jan 09, 2003 at 12:30:58PM +0200, Matthew Fincham wrote:
> > A telnet to the mailer fails (no route to host) - but while a ping is
> > successfully running (very confusing).
>
> As Steven Bellovin mentioned, this might mean that port 25 is being
> blocked by a firewall... it's possible that your ISP wants you to use
> their SMTP server for your outgoing mail, rather than trying to contact
> destination mailservers directly. (Prevents their customers from
> scanning for open SMTP servers and sending spam through them).
>
> > It seems like it is all "external" (I'm not sure what that means)
servers
> > which fail. I created a Yahoo mail account and tried to send mail to it,
> > from both my NetBSD (using mail) and Windows (using Outlook Express) and
the
> > NetBSD version failed with a "no route to host" error. Yet these two
systems
> > are on the same network. So I think it is some setting on the NetBSD
> > machine. Maybe a hosts issue??
>
> What did you set as the SMTP server in Outlook Express? Try using the
> same server as your "smart host" in /etc/mail/sendmail.cf (look for the
> "DS" line... E.g., change it to something like:
>
> # "Smart" relay host (may be null)
> DSmailserver.myisp.com
>

Yes, setting the smart relay host seems to work! :-)  I can only guess the
ISP is blocking the port as suggested. Thank you for your time in answering
my questions.

Matt