[TAG] [MAILER-DAEMON at localhost.localdomain: Undelivered Mail Returned to Sender]

[Claude Sutton]

Rick:

I attach a copy of my hosts file for your comments.

CSSJR



Quoting Rick Moen (rick at linuxmafia.com):

> Quoting Claude Sutton (claudesutton at cognisurf.com):
> 
> > I appreciate all of your efforts on my behalf, more than you know,
> > because most of this is totally over my head.  I will have to work on it
> > tomorrow.  Too late tonight.
> > 
> > I have no idea how the "local host" thing got in there. I will have to
> > trace back to see where it is.
> > 
> > Postfix came with whatever and I have no idea how to replace it, so that
> > will take time to research.
> > 
> > I have no idea what a null mailer is.
> 
> We're with you in all of this, Claude -- though there's a limit to what 
> any of us can do at a distance.  Believe me, we do sympathise, and
> applaud you as a new Linux user taking on some of the classic
> configuration tasks of the professional system administrator.
> 
> I try to be kind and understanding to new Linux users even when I'm
> tired and cranky -- and at the minimum apologise in advance to such folk
> for any excessive bluntness.
> 
> Your public DNS records claim that your domain's designated recipient
> machines for SMTP e-mail (termed "mail exchangers" or "MXes") are:
> 
>   mail.cognisurf.com (1st priority)
>   smtp.ipapp.com (2nd priority -- used if the other isn't reachable)
> 
> I'm guessing that the first of those is _your_ Linux box, the one on
> which you have Postfix configured -- and that the second is your ISP, 
> IP Applications Canada Corp. of British Columbia.
> 
> Ben noticed, recently, that both MXes refuse mail addressed to
> postmaster at cognisurf.com .  If I guessed correctly about you being the
> owner/administrator of "mail.cognisurf.com", then there's a problem
> on your machine _and_ the same problem on your ISP's SMTP host.
> 
> > That has finally sunk in on me.  However, until all of this came up, I
> > had no idea because everyone was accepting my emails.
> 
> Well, it's possible -- and you might be able to get by indefinitely not
> accepting mail to that address.  (The RFCs also dictate that you must
> accept mail at "abuse at cognisurf.com", and must accept mail _from_ the
> special address "<>" that is used for forwarding mail diagnostics.)
> 
> 
> In any event, unless I've messed up, I've recently made my SMTP host -- 
> which, by the way is primarily called "linuxmafia.com" but also has a
> secondary identity as "lists.linuxgazette.net" -- categorically accept
> mail prospectively from any sending address in the "cognisurf.com"
> domain, without requring that your domain accept mail at RFC-dictated
> mailboxes.
>  
> 
> > I thought that when I changed my "from" to attglobal.net that I was
> > being routed through their server and that at that point cognisurf had
> > nothing to do with it.
> 
> If you're having a problem with any particular piece of mail bouncing
> that you addressed to my machine from _anywhere_, please do send a copy
> of the bounce message to me with _full headers_ (command "h" in mutt),
> and I'll be glad to explain it to you.  
> 
> Before you ask, you can make your "please explain this bounce" message 
> not _itself_ bounce by sending it to "postmaster at linuxmafia.com" or 
> "postmaster at lists.linuxgazette.net", which accept all non-forged mail
> (as _likewise_ mandated by the RFCs).
> 
> > Remember, I am dialing in through wireless broadband with Alltel.  So
> > I thought that in that case I am using the Alltel system to get out
> > and the attglobal.net system tor replies.
> 
> We cannot comment until we see the full headers of that mail -- but
> definitely can and will, if/when you provide them.
> 
> 
> To answer one of the implied questions above:  A "nullrouter" is a
> deliberately simple, small SMTP server (daemon) package -- one just
> smart enough to drop off all outbound SMTP mail at an (e.g.) ISP
> "smarthost" that does all further routing and delivery of that mail.
> 
> The rather odd-sounding name is taken from the first-written example of
> that category.
> 
> One advantage of nullmailers over more-complex, general-purpose SMTP
> mail packages security:  With their limited feature set and small,
> more-easily-auditable source code, they typically have either perfect or
> nearly perfect security records.
> 
> Another advantage is extreme ease of setup and administration.
> 
> The drawback is that a nullmailer (by design) isn't very smart or
> capable -- it basically lobs everything at a designated "smarthost",
> which is then Somebody Else's Problem.  That's good in the sense that
> it's one thing fewer for you to have to manage; it's bad in the sense 
> that you cannot manage how your ISP handles your outbound mail.
> 
> It's almost koan-like:  The good news about a full-service Linux box is
> that you do it all yourself.  The bad news is the same as the good news.
> 
> 
> As to the other implied question:  I'm betting that
> "localhost.localdomain" is something that Postfix picked up from
> /etc/hosts because you there is _not_ a specifically declared hostname
> in Postfix's main.cf
> 
> I'm thinking you'll want to read these two snippets:
> 
> http://www.postfix.org/STANDARD_CONFIGURATION_README.html#stand_alone
> http://www.postfix.org/STANDARD_CONFIGURATION_README.html#fantasy
> 
> (Sadly, I'm a little out of my depth, here, having never administered or
> configured Postfix.)
> 
> "localhost" is a default machine identity that always exists for any
> machine with a TCP/IP presence.  If your machine keeps coming up as
> "localhost" or "localhost.localdomain", then probably you're missing a 
> line that ought to be in /etc/hosts.  For example, my server's
> /etc/hosts file consists of these contents:
> 
>   127.0.0.1	localhost.localdomain	localhost
>   198.144.195.186	linuxmafia.com	www.linuxmafia.com  uncle-enzo enzo 
>   198.144.195.187  cache 
>   198.144.195.188 airport         airport.deirdre.org   #802.11b base stn.
>   #198.144.195.189 macaroni       macaroni.deirdre.org  #not in service
>   198.144.195.190 emperor         emperor.deirdre.org
> 
>   # printers
>   10.0.1.213      lexx
> 
>   # static IPs for installfests
>   10.0.1.5	kenny
>   # The historic "kitchen" k6 box has been given away.  A replacement may arise.
>   10.0.1.215      kitchen cthulhu cthulhu.linuxmafia.com
>   10.0.1.216      yakko
>   10.0.1.217      wakko
>   10.0.1.218      dot
> 
>   # The following lines are desirable for IPv6 capable hosts
>   ::1     ip6-localhost ip6-loopback
>   fe00::0 ip6-localnet
>   ff00::0 ip6-mcastprefix
>   ff02::1 ip6-allnodes
>   ff02::2 ip6-allrouters
>   ff02::3 ip6-allhosts
> 
> Notice the first two lines.  The second is my _real_ IP and hostname(s).
-------------- next part --------------
127.0.0.1 localhost.localdomain localhost mythinkpad

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts