[plug] Sendmail - Smart host not working

[Ryan]

I've seen this on Debian as I have a webmail box behind a gateway that
uses the gateway as a smart host (another sendmail install).  The exact
reason was because I couldn't be bothered configuring MailScanner on two
hosts :)

This problem you have sounds a little different, but this may apply; as
essentially sendmail on the webmail box was trying to delivery
everything itself and failing as it was tripping up on the
professionally dodgy DNS setup here and thinking it should deliver
everything to itself and ignore the fact it should be using a smart
host.

My problem was I was using some smart hosts directive I found on the
sendmail site when I should have been using nullclient things.  If that
is not vague enough, then "I followed some directions I found elsewhere
and they didn't work" :)

Try putting this in sendmail.mc and regenerating the cf:

FEATURE(`nullclient', my.smarthost.my.domain.com)dnl

>From what I tried it HAD to be an address, not an IP, but I am probably
wrong there.  Just /etc/hosts it to make it work if you can't dodgy up
DNS internally to achieve it.

Once the cf is regenerated, it will have your host in 3 spots:

ryan at webmail:/etc/mail$ grep -n -B1 my.smarthost.my.domain.com
sendmail.cf
95-# "Smart" relay host (may be null)
96:DSmy.smarthost.my.domain.com
--
123-# ($R has precedence for unqualified names if FEATURE(stickyhost) is
used)
124:DHmy.smarthost.my.domain.com
--
137-# who I masquerade as (null for no masquerading) (see also $=M)
138:DMmy.smarthost.my.domain.com

Is that any different to what you already had?  Does it work any better
now?

HTH,

Ryan

On Fri, 2003-08-01 at 10:49, Andrew Carson wrote:
> Have a very perplexing problem here.. hoping someone has seen similar or knows
> the answer.
> sendmail-8.11.6-25.73 on a RH7.3 box  It sits behind a firewall and has no
> access to external DNS, so cf file is compiled with smart host entry, pointing
> to a machine that is running fine as a smart host for another mail server.  I
> also have accept_unresolvable_domains and accept_unqualified_senders compiled
> into the cf file.   The smart host is running exim.  I have the appropriate
> settings in the exim config file, that is: host_accept_relay and route_list.
> The problem.  Outgoing mail, even with the smart host set, *still* gets stuck
> in the queue with a "deferred" error due to host map: lookup for the
> destination domain, and mail coming in passes through the exim mail gateway
> without a problem.. and then gets stuck at sendmail with the same problem. 
> I've been ripping my hair out for days on this.. does anyone have an idea?