Sendmail- Is this correct.?

Tue Apr 12 05:21:07 UTC 2005

On Tue, 2005-04-12 at 13:30 +0900, Mark Sargent wrote:
> Paul Howarth wrote:
> 
> > Mark Sargent wrote:
> >
> >> Mark Sargent wrote:
> >>
> >>> Paul Howarth wrote:
> >>>
> >>>> On Mon, 2005-04-11 at 16:04 +0900, Mark Sargent wrote:
> >>>>  
> >>>>
> >>>>> Hi All,
> >>>>>
> >>>>> I am giving this a whirl on a machine at work. I've set it to use 
> >>>>> our provider to relay(right terminology.?) Ok, I set up an account 
> >>>>> in Evolution that uses smtp:localhost.localdomain and sent a mail 
> >>>>> to myself. I then checked with Thunderbird to see if the mail was 
> >>>>> successful, but, nothing. I'm sure I've missed something very 
> >>>>> fundamental. Below is the only section I changed in my .mc file,
> >>>>>
> >>>>> dnl define(`SMART_HOST',`smtp.feel.to')
> >>>>>
> >>>>> Anything else need adjusting/tweaking..? Cheers.
> >>>>>   
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> You need to delete the "dnl", which means "delete to new line". It's
> >>>> m4's way of commenting things out.
> >>>>
> >>>> Paul.
> >>>>  
> >>>>
> >>> Hi All,
> >>>
> >>> thanx Paul. Paul, is there a way to confirm that the sendmail.cf is 
> >>> now sending via smtp.feel.to as the test mail is still not 
> >>> arriving..? Cheers.
> >>>
> >>> Mark Sargent.
> >>>
> >> Hi All,
> >>
> >> ok, I checked /var/log/maillog and found this,
> >>
> >> Apr 11 16:51:06 localhost sendmail[7896]: j3B7p5JJ007893: 
> >> to=<powderkeg at snow.email.ne.jp>, 
> >> ctladdr=<coolboarderguy at localhost.localdomain> (500/500), 
> >> delay=00:00:01, xdelay=00:00:01, mailer=relay, pri=120395, 
> >> relay=sv.feel.to. [211.10.15.172], dsn=2.0.0, stat=Sent (j3B7oLl09915 
> >> Message accepted for delivery)
> >>
> >> That looks like success from my end, yes..? But, it's not reaching my 
> >> inbox for the address I'm mailing to. Anything I should be double 
> >> checking with this..? Cheers.
> >
> >
> > Your mail server is sending out mail with a bogus from: address of 
> > coolboarderguy at localhost.localdomain. No sensible mail server will 
> > accept mail from unresolvable domains like that. You need to use a 
> > real domain name. Look up masquerading in /usr/share.sendmail-cf/README
> >
> > Paul.
> >
> Hi All,
> 
> Paul, I have read this section at the tutorial site,
> 
> You can have your host masquerade as another by using this macro:
> 
>         MASQUERADE_AS(`host.domain')
> 
> Masquerading is a very important part of a client/server mail hub 
> configuration. Any machine configured like this will rewrite the SMTP 
> From: header of all outbound mail to look like the message came from the 
> address you're masquerading as. This address /must/ be an address record 
> in DNS, not simply a CNAME, or the remote end will canonicalize the 
> address back to the original name.
> 
> and was wondering, as it's a requirement to have the address in a DNS 
> record, does this have to be a registered domain name, as we don't have 
> 1. If no, then I can just masquerade as anyone(not that I really want 
> to)..? Our router is our DNS, so we would have to add this record to it, 
> yes..? Sorry for the mundane questions. Cheers.
----
given the low cost of obtaining a domain name and various 'free dns'
systems - i.e. mydomain.com $8.50 per year for domain registration and
free dns, it seems to make sense to have your own domain.

I sort of believed that if you used 'smart host' that if the smart host
that you chose was the smtp server provided by your ip connection, that
simply by virtue of your ip address, it would pass the mail through. I
have never put it to the test as I have always had my own domain name
for one very good reason...my domain name/hence email addresses at my
domain name are entirely portable and thus I am not subject to the whims
of internet providers of mailboxes.

Thus - if I consider my situation...

# host 68.228.225.160 68.2.16.30
Using domain server:
Name: 68.2.16.30
Address: 68.2.16.30#53
Aliases:

160.225.228.68.in-addr.arpa domain name pointer
ip68-228-225-160.ph.ph.cox.net.

# host ip68-228-225-160.ph.ph.cox.net
ip68-228-225-160.ph.ph.cox.net has address 68.228.225.160

further dissection of one of my recent emails to this list...

Red Hat received my email...
Received: from mx1.redhat.com (mx1.redhat.com [172.16.48.31]) by int-
mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id j3C3XTO27182 for
<fedora-list at redhat.com>; Mon, 11 Apr 2005 23:33:29 -0400

>From Cox.net SMTP server (my smart host)
Received: from fed1rmmtao12.cox.net (fed1rmmtao12.cox.net
[68.230.241.27]) by mx1.redhat.com (8.12.11/8.12.11) with ESMTP id
j3C3XSQJ028164 for <fedora-list at redhat.com>; Mon, 11 Apr 2005 23:33:28
-0400

>From my mail server at my house (note, reverse dns won't work)
Received: from linuxserver.azapple.com ([68.228.225.160]) by
fed1rmmtao12.cox.net (InterMail vM.6.01.04.00 201-2131-118-20041027)
with ESMTP id
<20050412033317.IJEV13819.fed1rmmtao12.cox.net at linuxserver.azapple.com>
for <fedora-list at redhat.com>; Mon, 11 Apr 2005 23:33:17 -0400

>From my workstation - also not resolvable via dns - note private IP #
Received: from lin-workstation.azapple.com (lin-workstation.azapple.com
[192.168.2.10]) by linuxserver.azapple.com (8.12.11/8.12.11) with ESMTP
id j3C3XCQr008754 for <fedora-list at redhat.com>; Mon, 11 Apr 2005
20:33:12 -0700

--- 
since cox.net is my internet service provider and my ip address resolves
as ip68-228-225-160.ph.ph.cox.net I could probably set my system up to
masquerade as ip68-228-225-160.ph.ph.cox.net and it would actually
resolve - as per above

but that seems really stupid

and since cox.net blocks port 25 for all 'dynamic customers' in this
area, I have to use cox's smtp server as that is the only place that I
can make port 25 connections (ignoring of course, port 587 stuff) and
they direct me to smtp.west.cox.net - so I have set that as my 'smart
host' and I pretty much figure that even if my machine sent mail as
craig at localhost.localdomain that smtp.west.cox.net that it would accept
it but the larger problem was if there was a delivery problem, it
wouldn't know where to send the mail to.

Thus - any of these solutions are poor at best and the only logical
thing to do is to have your own domain OR don't run your own mail server
and simply set all your mail clients to use someone else's smtp server.

Craig