fetchmail->sendmail: 451 4.1.8 Domain does not resolve

This is probably one of the most FA'd of Qs, judging from what I've
found on Google. That is, I've found many occurrences of the question,
but little that I can interpret as an answer.

I'm trying to pull mail with fetchmail. Until now I've been sending
and receiving mail with my trusty old Amiga, with an occasional use
of fetchmail on a Slackware 7 box. Both machines were on dialup.
But I've just gone over to an ADSL connection and put my home network
behind an OpenBSD box that I've set up as a gateway/firewall, and I'm
getting nothing but frustration. Fetchmail successfully gets into my
ISP's POP server, but when it tries to pass a message on to my local
machine's SMTP server for mutt to access, I get "SMTP error: 451 4.1.8
Domain of sender address <(E-Mail Removed)> does not resolve".
This happens not only on a newer Slack 9.1 box, but also on the old
Slack 7 box that worked fine when it dialed straight into an ISP.

I've heard tantalizing hints about how to make sendmail less picky,
although they're usually accompanied by warnings not to do it.
Besides, one look at sendmail.cf makes me want to steer well clear.
So that brings me back to trying to figure out why sendmail can't
resolve these addresses.

What do I have to do to make things work? My resolv.conf seems to
be OK; nslookup and dig have no trouble getting through the gateway
and looking up the domain names, and I can surf the web with no
problems. So what's going wrong, and why does it bite so many people?

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In comp.os.linux.networking Charlie Gibbs <(E-Mail Removed)>:
[..]
> I'm trying to pull mail with fetchmail. Until now I've been sending
[..]
> getting nothing but frustration. Fetchmail successfully gets into my
> ISP's POP server, but when it tries to pass a message on to my local
> machine's SMTP server for mutt to access, I get "SMTP error: 451 4.1.8
> Domain of sender address <(E-Mail Removed)> does not resolve".
[..]

Put this in sendmail.mc, rebuild sendmail.cf using m4 (see
cf/README if in doubt) and restart sendmail.

FEATURE(`accept_unresolvable_domains')dnl

Good luck

BTW
Use comp.mail.sendmail next time, the primary group for
sendmail related questions.

--
Michael Heiming (X-PGP-Sig > GPG-Key ID: 0xEDD27B94)
mail: echo (E-Mail Removed) | perl -pe 'y/a-z/n-za-m/'
#bofh excuse 115:
your keyboard's space bar is generating spurious keycodes.

In article <qmj152-(E-Mail Removed)>,
michael+(E-Mail Removed) (Michael Heiming) writes:

>In comp.os.linux.networking Charlie Gibbs <(E-Mail Removed)>:
>[..]
>> I'm trying to pull mail with fetchmail. Until now I've been sending
>[..]
>> getting nothing but frustration. Fetchmail successfully gets into
>> my ISP's POP server, but when it tries to pass a message on to my
>> local machine's SMTP server for mutt to access, I get "SMTP error:
>> 451 4.1.8 Domain of sender address <(E-Mail Removed)> does not
>> resolve".
>[..]
>
>Put this in sendmail.mc, rebuild sendmail.cf using m4 (see
>cf/README if in doubt) and restart sendmail.
>
> FEATURE(`accept_unresolvable_domains')dnl
>
>Good luck
>
>BTW
>Use comp.mail.sendmail next time, the primary group for
>sendmail related questions.

I know absolutely nothing about sendmail, but it seems it's
time to learn. Thanks for the pointer - I'll wander over to
comp.mail.sendmail and look for some FAQs.

(I've heard it said that sendmail.cf looks as if someone was
banging his head on the keyboard, and that after fiddling with
it for a while, you will too.)

--
/~\ (E-Mail Removed)lid (Charlie Gibbs)
\ / I'm really at ac.dekanfrus if you read it the right way.
X Top-posted messages will probably be ignored. See RFC1855.
/ \ HTML will DEFINITELY be ignored. Join the ASCII ribbon campaign!

In comp.os.linux.networking Charlie Gibbs <(E-Mail Removed)>:
> In article <qmj152-(E-Mail Removed)>,
> michael+(E-Mail Removed) (Michael Heiming) writes:

>>In comp.os.linux.networking Charlie Gibbs <(E-Mail Removed)>:
>>[..]
>>> I'm trying to pull mail with fetchmail. Until now I've been sending
>>[..]
>>> getting nothing but frustration. Fetchmail successfully gets into
>>> my ISP's POP server, but when it tries to pass a message on to my
>>> local machine's SMTP server for mutt to access, I get "SMTP error:
>>> 451 4.1.8 Domain of sender address <(E-Mail Removed)> does not
>>> resolve".
>>[..]
>>
>>Put this in sendmail.mc, rebuild sendmail.cf using m4 (see
>>cf/README if in doubt) and restart sendmail.
>>
>> FEATURE(`accept_unresolvable_domains')dnl
>>
>>Good luck
>>
>>BTW
>>Use comp.mail.sendmail next time, the primary group for
>>sendmail related questions.

> I know absolutely nothing about sendmail, but it seems it's
> time to learn. Thanks for the pointer - I'll wander over to
> comp.mail.sendmail and look for some FAQs.

You shouldn't need more, the above line is all you need to make
your sendmail accept unresolvable domains. sendmail.mc says in
the first few lines how to rebuild sendmal.cf. Thought you'd look
at yours and hopefully have the same comment:

dnl This is the sendmail macro config file. If you make changes to this file,
dnl you need the sendmail-cf rpm installed and then have to generate a
dnl new /etc/sendmail.cf by running the following command:
dnl
dnl m4 /etc/mail/sendmail.mc > /etc/sendmail.cf
dnl

Or to /etc/mail/sendmail.cf, whatever your system uses. And
restart sendmail, that's all, no rocket science involved.

> (I've heard it said that sendmail.cf looks as if someone was
> banging his head on the keyboard, and that after fiddling with
> it for a while, you will too.)

There's no reason to ever touch sendmail.cf, unless you are
really sure you know what you are doing, but then you wouldn't
ask. Concentrate on how to setup sendmail.mc for your needs, 'm4'
will then do anything for you.

--
Michael Heiming (X-PGP-Sig > GPG-Key ID: 0xEDD27B94)
mail: echo (E-Mail Removed) | perl -pe 'y/a-z/n-za-m/'
#bofh excuse 180: ether leak

In article <77j252-(E-Mail Removed)>,
michael+(E-Mail Removed) (Michael Heiming) writes:

>In comp.os.linux.networking Charlie Gibbs <(E-Mail Removed)>:

>> In article <qmj152-(E-Mail Removed)>,
>> michael+(E-Mail Removed) (Michael Heiming) writes:

<snip>

>>>Put this in sendmail.mc, rebuild sendmail.cf using m4 (see
>>>cf/README if in doubt) and restart sendmail.
>>>
>>> FEATURE(`accept_unresolvable_domains')dnl

>> I know absolutely nothing about sendmail, but it seems it's
>> time to learn. Thanks for the pointer - I'll wander over to
>> comp.mail.sendmail and look for some FAQs.
>
>You shouldn't need more, the above line is all you need to make
>your sendmail accept unresolvable domains. sendmail.mc says in
>the first few lines how to rebuild sendmal.cf. Thought you'd look
>at yours and hopefully have the same comment:

<snip>

Odd - my machine doesn't have a file called sendmail.mc. I started
off by looking in /etc/mail, but finally ran find on the whole file
system and came up empty. I'm running Slackware 9.1 - is it different
for this particular flavour of Linux?

Meanwhile, I'm plowing through comp.mail.sendmail in search of
Enlightenment...

--
/~\ (E-Mail Removed)lid (Charlie Gibbs)
\ / I'm really at ac.dekanfrus if you read it the right way.
X Top-posted messages will probably be ignored. See RFC1855.
/ \ HTML will DEFINITELY be ignored. Join the ASCII ribbon campaign!

On 26 Oct 04 18:13:04 -0800, "Charlie Gibbs" <(E-Mail Removed)>
wrote:

>>You shouldn't need more, the above line is all you need to make
>>your sendmail accept unresolvable domains. sendmail.mc says in
>>the first few lines how to rebuild sendmal.cf. Thought you'd look
>>at yours and hopefully have the same comment:
>
><snip>
>
>Odd - my machine doesn't have a file called sendmail.mc. I started
>off by looking in /etc/mail, but finally ran find on the whole file
>system and came up empty. I'm running Slackware 9.1 - is it different
>for this particular flavour of Linux?

If you install webmin, you can change the sendmail settings from
within the webmin administration webpages. I use it on slackware and
it works very good.

Google on 'webmin' and install it.

Regards, Rob

In comp.os.linux.networking Charlie Gibbs <(E-Mail Removed)>:
> In article <77j252-(E-Mail Removed)>,
> michael+(E-Mail Removed) (Michael Heiming) writes:

>>In comp.os.linux.networking Charlie Gibbs <(E-Mail Removed)>:

>>> In article <qmj152-(E-Mail Removed)>,
>>> michael+(E-Mail Removed) (Michael Heiming) writes:
[..]

>>>>Put this in sendmail.mc, rebuild sendmail.cf using m4 (see
>>>>cf/README if in doubt) and restart sendmail.
>>>>
>>>> FEATURE(`accept_unresolvable_domains')dnl


> Odd - my machine doesn't have a file called sendmail.mc. I started
> off by looking in /etc/mail, but finally ran find on the whole file
> system and came up empty. I'm running Slackware 9.1 - is it different
> for this particular flavour of Linux?

Tried something like this:

find / -name "*sendmail*.mc"

Or and consult the sendmail docs that came with your distro,
can't imagine you don't have some *.mc file for sendmail, is 'm4'
installed at least?

--
Michael Heiming (X-PGP-Sig > GPG-Key ID: EDD27B94)
mail: echo (E-Mail Removed) | perl -pe 'y/a-z/n-za-m/'
Please don't send questions directly to me, ask here.
#bofh excuse 155: Dumb terminal

"Charlie Gibbs" <(E-Mail Removed)> writes:

>Odd - my machine doesn't have a file called sendmail.mc. I started
>off by looking in /etc/mail, but finally ran find on the whole file
>system and came up empty. I'm running Slackware 9.1 - is it different
>for this particular flavour of Linux?

There are many sample *.mc files under /usr/share/sendmail and its
subdirectories, but these are only present if you installed the
sendmail-cf-8.12.10-noarch-1 package.

--
Mark Cudworth

In article <8g2452-(E-Mail Removed)>,
michael+(E-Mail Removed) (Michael Heiming) writes:

>In comp.os.linux.networking Charlie Gibbs <(E-Mail Removed)>:
>
>> Odd - my machine doesn't have a file called sendmail.mc. I started
>> off by looking in /etc/mail, but finally ran find on the whole
>> file system and came up empty. I'm running Slackware 9.1 - is it
>> different for this particular flavour of Linux?
>
>Tried something like this:
>
>find / -name "*sendmail*.mc"

Aha! It found

/usr/share/sendmail/cf/cf/sendmail-slackware-tls.mc
/usr/share/sendmail/cf/cf/sendmail-slackware.mc

There are all sorts of other .mc files in /usr/share/sendmail/cf/cf too.

>Or and consult the sendmail docs that came with your distro,
>can't imagine you don't have some *.mc file for sendmail, is 'm4'
>installed at least?

I do have m4. So now I have something to start from (after saving
my current sendmail.cf, of course! :-). Thanks for the help.

--
/~\ (E-Mail Removed)lid (Charlie Gibbs)
\ / I'm really at ac.dekanfrus if you read it the right way.
X Top-posted messages will probably be ignored. See RFC1855.
/ \ HTML will DEFINITELY be ignored. Join the ASCII ribbon campaign!

In article <(E-Mail Removed)>,
(E-Mail Removed)lid (Charlie Gibbs) writes:

> In article <8g2452-(E-Mail Removed)>,
> michael+(E-Mail Removed) (Michael Heiming) writes:
>
>> In comp.os.linux.networking Charlie Gibbs <(E-Mail Removed)>:
>>
>>> Odd - my machine doesn't have a file called sendmail.mc. I started
>>> off by looking in /etc/mail, but finally ran find on the whole
>>> file system and came up empty. I'm running Slackware 9.1 - is it
>>> different for this particular flavour of Linux?
>>
>> Tried something like this:
>>
>> find / -name "*sendmail*.mc"
>
> Aha! It found
>
> /usr/share/sendmail/cf/cf/sendmail-slackware-tls.mc
> /usr/share/sendmail/cf/cf/sendmail-slackware.mc
>
> There are all sorts of other .mc files in /usr/share/sendmail/cf/cf
> too.
>
>> Or and consult the sendmail docs that came with your distro,
>> can't imagine you don't have some *.mc file for sendmail, is 'm4'
>> installed at least?
>
> I do have m4. So now I have something to start from (after saving
> my current sendmail.cf, of course! :-). Thanks for the help.

OK, maybe Slackware is a little disorganized on this box, but I managed
to track things down. /usr/share/sendmail/cf/cf/sendmail-slackware.mc
already contained the following lines:

dnl# Turn this feature on if you don't always have DNS, or enjoy junk mail:
dnl FEATURE(`accept_unresolvable_domains')dnl

The system seems to be pretty picky about which directory it runs in,
but I got it to build a new sendmail.cf with the following steps:

root@tuxmove:~# cd /etc/mail
root@tuxmove:/etc/mail# cp -p sendmail.cf sendmail.cf.ori
root@tuxmove:/etc/mail# cd /usr/share/sendmail/cf/cf
root@tuxmove:/usr/share/sendmail/cf/cf# cp sendmail-slackware.mc sendmail.mc
root@tuxmove:/usr/share/sendmail/cf/cf# vi sendmail.mc
(remove "dnl " prefix from the FEATURE line)
root@tuxmove:/usr/share/sendmail/cf/cf# m4 sendmail.mc >/etc/mail/sendmail.cf

At this point I kicked sendmail with a SIGHUP, then tried fetchmail
again. Presto! A piece of mail, complete with a 3-megabyte attachment,
flowed smoothly into my machine and was happily picked up by mutt.

Thanks again, everyone, for your help. I've filed this thread in my
personal archives in case I need to do it again sometime.

--
/~\ (E-Mail Removed)lid (Charlie Gibbs)
\ / I'm really at ac.dekanfrus if you read it the right way.
X Top-posted messages will probably be ignored. See RFC1855.
/ \ HTML will DEFINITELY be ignored. Join the ASCII ribbon campaign!