Question about sendmail...

[Craig White]

On Fri, 2005-10-28 at 06:18 +0200, Alexander Dalloz wrote:
> Am Fr, den 28.10.2005 schrieb Philip Prindeville um 4:26:
> 
> > I'm running FC3 (updated) on a handful of machines.
> > 
> > I have a single IP address, with a NATing router set to that
> > address.  I have a domain, and an MX which points through
> > the router at my mail server (or rather, the router is configured
> > to port-forward 25, 143, etc to the mail server).
> > 
> > I also have several mail clients on my 192.168.1.x network.
> > 
> > The issues are the following:
> > 
> > * the clients have a smart host (DS) defined as the mail relay,
> >    but they canonical its name and then look it up in the DNS,
> >    trying to contact it on the external IP address (and not its
> >    internal 192.168.1.x address in the /etc/hosts file).  My
> >    /etc/nsswitch.conf file is unmodified.
> > 
> > * the clients then try to relay the email with a sender's envelope
> >    address as user at host.my-domain, which the relay rejects
> >    because "host.my-domain" doesn't resolve in the DNS.
> > 
> > * I should probably have define(`LOCAL_RELAY', `:$S') to
> >    handle forwarding everything to the mail server.
> > 
> > I used to know all of this stuff once upon a time...
> 
> > -Philip
> 
> Reading this I have the strong feeling it was you I was talking to in
> #sendmail on freenode this evening (night) :)
> 
> I would vote for running a local DNS (bind) service, in conjunction with
> DHCP and dynamic zone updates. That would be ideal. And for unqualified
> sender addresses use the masquerading features of Sendmail.
> 
> On the other hand you may go this route: do not run local Sendmail
> daemons, but use the submission process to directly feed outgoing mail
> from inner clients to the central mail hub. Have a look at
> /etc/mail/submit.mc. Comment out (remove the leading "dnl") for
> 
> define(`confDIRECT_SUBMISSION_MODIFIERS',`C')
> 
> and even add a line
> 
> FEATURE(`nocanonify', `canonify_hosts')
> 
> and finally change the IP in
> 
> FEATURE(`msp', `[127.0.0.1]')dnl
> 
> to the one of the central mail hub.
> 
> Please see http://www.sendmail.org/m4/msp.html or better the current
> cf/README coming with your Sendmail on Fedora. Many discussion about
> this topic to be found through
> 
> http://groups.google.com/groups?hl=en&lr=&c2coff=1&sa=X&oi=groupst&q=Sendmail+confDIRECT_SUBMISSION_MODIFIERS
> 
> Hope it helps.
----
the alternative to running local dns is to use /etc/hosts to define a
locally available name that doesn't resolve properly via dns isn't it?
It would strike me as simpler to add the name to /etc/hosts but I still
prefer just using the ip address in sendmail.mc

Craig


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