[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: delivery refusal (DNS not listed)



Thanks a lot for the help with getting my mail working. In the end I did have to generate a new sendmail.cf (and upgrade sendmail because I couldn't find sendmail-cf that was the same version as comes with RH5.2). This made me invent a new sendmail.cw (I put "zahav.net.il username" into it which seems to work). All I can say is that the documentation for sendmail is even worse than I had been lead to beleave.

	David

Quoting gaal@forum2.org <gaal@forum2.org>:
> On Sat, Mar 06, 1999 at 10:14:48PM +0200, David Resnick wrote:
> 
> > ... while talking to zc.mx.aol.com.:
> > >>> MAIL From:<dmr@localhost.localdomain> SIZE=849
> > <<< 550 <dmr@localhost.localdomain>... Sender domain not found in DNS (see RFC
> > 1123, sections 5.2.2 and 5.2.18).
> > 554 xyz@aol.com... Service unavailable
> > 
> > --------------------------------------------
> > 
> > The problem is obvious, the solution is just a little bit trickier ;).
> 
> Actually it's not at all trivial :-)
> I'm assuming a pretty standard RH system, with sendmail. YMMV greatly!
> 
> > Should I be sending my mail via the same (POP) server that sends my
> > mail? There is no place that I've found where I need to put the name of
> > my outgoing mail server, like there is in the netscape mail client. Or do
> > I need to somehow change my domain name to something that is true?
> 
> You may either send mail yourself, or relay it through your ISP's
> mail server. Some people prefer the first option because it's easier
> to set up and because it offers a little more privacy; some will say
> it's more "correct" to relay your mail, because you aren't a constantly
> connected host (are you?), and therefore won't be available to receive
> errors and bounces when they arrive. Obviously, choosing the latter
> means you have a little less control over how your mail is dealt with.
> 
> Let's go for the second approach. First, give your machine a qualified
> name. It doesn't have to be something that DNSes around the world know
> about, since we'll not be using it on our mail envelope, but you need
> one anyway. Your best choice will be
> 	whateveryoulike.your.isp.com
> that is, you only get to choose the hostname bit.
> 
> Now, tell your sendmail you'll be relaying your mail through your ISP.
> Edit /etc/sendmail.cf (make a backup please!).
> 1. Find the line that says "DS". It's probably empty, make it
> 	DSmailgw.isp.com
> or whatever your ISP wants you to put there (line must start with DS,
> and no space between the DS and the host name).
> 
> 2. Also, find the line "O HoldExpensive" and change the value to "true",
> thus allowing your server not to attempt to dequeue messages all the
> time.
> 
> 3. Now, in the line with "DM" put
> 	DMyour.isp.com
> for example, if you're with Netvision put "DMnetvision.net.il".
> 
> 4. restart sendmail with "/etc/rc.d/init.d/sendmail restart".
> 
> Do several test messages. YOU MAY HAVE PROBLEMS NOW. Especially
> important in this stage is to (a) keep a backup of all your config
> files first and (b) add "-k" (keep) to your fetchmail options, since
> incoming mail may be munged too (fetchmail uses your local sendmail).
> 
> Here are several things that may or may not be needed, depending on
> your ISP etc.
> 
> 5. allow your mail clients to control the "From: " header. You can
> do this by adding your userid (and that of other users) to the sendmail
> trusted users: find the section and add a line like
> 	Tuserid
> (and restart sendmail)
> 
> 6. tell your sendmail what its official domain name is (don't do this
> unless you have to):
> 	Dj$w.isp.com
> 
> 7. If your mail gateway refuses to accept your mail because it doesn't
> believe you when you say you are "foo.isp.com", you'll have to masquerade
> your envelope as well as your headers. This is a little more tricky, and
> works like this:
> 
> 	a) install the package sendmail-cf*rpm
> 	b) cd /usr/lib/sendmail-cf/cf
> 	c) cp redhat.mc my.very.own.mc
> 	d) echo "MASQUERADE_AS(your.isp.com)"  >> my.very.own.mc
> 	e) echo "FEATURE(masquerade_envelope)" >> my.very.own.mc
> 	f) take a very deep breath. consult your local deity.
> 	g) m4 ../m4/cf.m4 my.very.own.mc > my.very.own.cf
> 	h) edit the resulting file, and manually apply any changes
> 	   you had made to your previous /etc/sendmail.cf .
> 	i) put this file as your new /etc/sendmail.cf, restart sendmail
> 
> (if you must forget one of these steps, don't let it be step f).
> 
> 
> That should be it. Please don't believe the previous sentence, and
> test and retest your mail config. Losing mail is painful. Make
> backups of everything. Don't remove messages from the POP server
> till you're done.
> 
> As a final note, when you upgrade your sendmail, apply any changes
> you've made to /etc/sendmail.cf . This may mean regenerating the
> file as illustrated in step 7, especially if it's a major sendmail
> upgrade.
> 
> Hope this helps,
> Gaal
> 
> --
> believing is seeing
> gaal@forum2.org
> http://www.forum2.org/gaal/