SMTP AUTH, Sendmail client to Postfix server
 

I'm hoping someone here can help, as I've been beating my head on the wall for a week now with little advancement.

I've found a number of tutorials on setting this up, however none of them have gotten me 100% of the way there.

Here's my situation: home-based Fedora server (Core 8), running sendmail 8.14.2-1. Connecting to hosting company's smtp server over port 587, to bypass Verizon's blocking of port 25.

My /etc/mail/sendmail.mc file looks like this (comment lines removed):

My /etc/mail/auth/client-info file looks like this (username and password obscured):

I can successfully send a mail manually, as shown here:

But when I try to send a mail message from my server, it fails and sends back this bounce message:

I'm at my wit's end (not that long a trip, I'll grant you), can anyone help?

Hi,

Take a look at this thread here at LQ (specially post #2)

Regards

Thanks for the reply bathory, but the URL didn't come through, can you repost?

Oups sorry for that
Here is the link: http://www.linuxquestions.org/questi...t-port-690852/

Regards

I was able to find it, but strangely the URL itself didn't work...it would redirect to some other unrelated post, but I used some of the words from the URL in a search and found the post you were talking about.

Everything mentioned in that post, and the external article referenced, I have done, and it still fails.

Here is the relevant lines from /var/log/maillog from my most recent attempt:

I still think this means my sendmail isn't doing the auth correctly, or at all, but I can't figure out why.

You miss LOGIN from the mechanisms:
but you use it in
Try to use "M:PLAIN" and see if it works.

I added LOGIN to the mechanisms and recreated sendmail.cf, that should have fixed it also, right? I'm loathe to use PLAIN since that is completely in the clear (not that LOGIN is that much better with just base64 encoding)

Still fails:
Could there be something wrong with my SMART_HOST or the various MASQUERADE options?

Hi,

I've reread sendmail documentation and if you want to use base-64 encoded username/password in /etc/mail/authinfo, you have to replace ":" with "=", like this:
HTH

Regards

I'm still getting the following:

(reason: 554 5.7.1 <rickg@datarealm.com>: Relay access denied)

I'm ready to start tearing my hair out.

Hi,

Are you sure you use:
If yes, try to remove the 2nd line, the port and maybe the U part from authinfo:
and see if it works!

Ok, I verified the sendmail.mc lines were as I posted (I had done cut-and-pastes, so was pretty sure).

I removed port from the first line, and the line that had just the port, tested that and it failed. I then removed the U: from the remaining line, and that also failed. I then, on a guess, tried to have both versions of the line...with the FQDN of the host, but with and without the port. That also failed.

Here is the current /etc/mail/auth/client-info file:
Here is the last bounced email showing the failure:

I really appreciate the continued help in trying to diagnose/fix this.

I'm just curious because I've just tested this setup and it works :scratch:

Til now I was using out corporate mail server (on port 25) as a smarthost for sendmail running on my box at home.
So I've changed the relay port in sendmail.mc to 587 and it also worked, when I removed the port from authinfo. I've used tcpdump and saw that sendmail was contacting the smarthost on port 587 in both cases (with or without the port), but in the former case I was getting a DSN with a "No AUTH command command has been given" error.

Maybe your smarthost does not like the from: address, so change it to something other than root@localhost.local domain and test.
I don't know what else to think

Regards

I've been sending test emails just by using the command:

How would I set the from? I though the MASQUERADE options were supposed to do that?

Use:
Apparently masquerade does not work (default for root)

I had to do it this way:

Still failed, no difference in the message.

I've tried running sendmail in a higher level of debugging messages, but I was not able to determine from the output if it was correctly doing authentication or not, do you have any recommendations on that, maybe better diagnostic messages would help.

What kind mail are you running? The -f option is used by sendmail to define the from: address.
Anyway I've managed to send mail through smtp2.datarealm.com, using your credentials (edit the post above to remove them, because they can be used by others too)
Anyway I've attached my sendmail.mc (rename .txt to .mc) and test

Regards

I'm getting some errors trying to process it. I fixed the first by creating the authinfo file and .db hash, sourced from the client-info file I had been using.

There was a reference to include a file which I don't have, so I commented that out, but there are still issues:

I copied the VERSIONID line from my original sendmail.mc, but that didn't seem to help.

Are we on the same sendmail version? The RPM for mine is: sendmail-8.14.2-1.fc8 (as delivered with Fedora Core 8).

Use the include statement in your sendmail.mc (include(`/usr/share/sendmail-cf/m4/cf.m4')dnl)
Other than that I guess you can keep the rest as is

Ok, missed the fact I had that line in my original sendmail.mc. Copied it in, re-did the m4 command and restarted, tried a test (setting the to: address to an alternate email address of mine, and setting the from: address to the same account that I'm trying to use to authenticate.

Test still failed, results here:

Should we just give up, or do you think we are close? Really appreciate the time you've put into this so far, either way.

Rick

Well, I don't think we're close at all. In fact you're still getting the same "Relay access denied" error!
I guess you use an authinfo, like this:
Other than that you can, try for once to use plain username/password and M:PLAIN in authinfo and see if you get something different.

*sigh* That didn't change anything.

I keep coming back to the thought that my sendmail, acting as a client, is not properly doing the authentication bit, since both you and I have manually connected to the SMTP daemon at my provider and made it work. How else can we test this?

Did you try the PLAIN auth option just in case? Or setup a mail client, like Thunderbird, to use directly your ISP mail server.

I didn't use telnet on port 587 of your provider, but a mail command as in post #14.

If you feel adventurous you can install a sniffer like wireshark and watch the traffic from you box to the remote smtp server on port 587 and see if sendmail sends the correct credentials.

I did try the plain, that was what my last post was about, sorry, I don't think I was very clear on that. PLAIN didn't help. Thunderbird is my Windows-based email client, and it works all the time.

I did do the telnet to port 587, and ran the SMTP commands manually, using "AUTH LOGIN" and the base-64 encoded versions, and that did work.

I guess that's what I'll have to try...it's either that, or just give up at this point.

By, using telnet on smarthost port 587, you bypass sendmail, so it works. The strange thing is that sedmail is not working as a client to the smarthost with the same credentials.
Do you have cyrus-sasl or cyrus-sasl-2 installed? What gives?

Here's what I got trying that commmand:

And thinking ahead, here's my sasl RPM list:
And currently running sasl processes:

Well it was expected that sasl2 is installed, but I thought to ask anyway.
MAybe you can increase logging by adding
in sendmail.mc, or starting sendmail from CLI using:
and watch the logs

I just noticed these messages that were pulled out of the system logs by "logwatch":

Could those be related?

Ok, it looks like my guess was right, sendmail isn't doing the authentication or doing it incorrectly, if I'm reading this right. However, I've no clue as to why...here's the entire /var/log/maillog contents, starting from the last restart of sendmail with the above changed added in.

Strangely, it doesn't look like it's actually trying to contact the SMART_HOST relay, but it is just contacting itself??

Regarding the certs, I guess you're still using the sendmail.mc from my sendmail that is configured with TLS. Remove those lines in your sendmail.mc and recreate sendmail.cf.

At the beginning of the logs there is the connection to your sendmail while it's receiving your mail. The connection to smarthost start with:
I think that in fact this is your problem, i.e. mech is empty, instead of mech=LOGIN, but I don't know why is that happening!

I couldn't tell for certain what entries to comment out, can you clarify?

Remove the following:

Ok, got those out, less errors on the startup now.

Still getting that "mech=" blank entry, scratching my head on that one too.

Since I'm out of ideas, I suggest you to follow this tutorial written to use gmail as a smarthost on port 587.
To create the ssl certificates read #3 here