[ZendTo] Issues with sending to external users

Fri Jan 13 16:14:13 GMT 2017

As Jules says, this error implies that your server is trying to send the
message direct to Google. But there are (at least) two issues with this:

   1. It looks to be that your server can talk IPv6 and is doing so direct
   to Google's mail servers, but that these are detecting a problem with your
   DNS records as they describe in the error response.

   2. If you're sending from an "@utoronto.ca" email address then there is
   an SPF record published in the DNS for the utoronto.ca domain saying
   that servers with IP addresses in the netblocks ip4:128.100.132.0/24 and
   ip4:128.100.46.0/24 should be sending out messages from "@utoronto.ca"
   addresses and others shouldn't really be.

As Jules says, the best thing is to get the emails sent from your server to
be relayed out through your organisation's central mail gateways/smarthosts.

Cheers,
Mike B-)

PS. Have just read your latest message: glad you've spotted the issue.

On 13 January 2017 at 15:37, Brian Novogradac <Brian.Novogradac at utoronto.ca>
wrote:

> Here is the error from my root mailbox
>
>
>
>
>
>    ----- The following addresses had permanent fatal errors -----
>
> <user at gmail.com>
>
>     (reason: 550-5.7.1 [2606:fa00:400:2006:250:56ff:fe92:282a] Our system
> has detected that)
>
>
>
>    ----- Transcript of session follows -----
>
> ... while talking to gmail-smtp-in.l.google.com.:
>
> >>> DATA
>
> <<< 550-5.7.1 [2606:fa00:400:2006:250:56ff:fe92:282a] Our system has
> detected that
>
> <<< 550-5.7.1 this message does not meet IPv6 sending guidelines regarding
> PTR
>
> <<< 550-5.7.1 records and authentication. Please review
>
> <<< 550-5.7.1  https://support.google.com/mail/?p=IPv6AuthError for more
> information
>
> <<< 550 5.7.1 . u130si1909083iod.170 - gsmtp
>
> 554 5.0.0 Service unavailable
>
>
>
> --v0DDJKOE005944.1484313560/send.utoronto.ca
>
> Content-Type: message/delivery-status
>
>
>
> Reporting-MTA: dns; send.utoronto.ca
>
> Received-From-MTA: DNS; localhost.localdomain
>
> Arrival-Date: Fri, 13 Jan 2017 08:19:19 -0500
>
>
>
> Final-Recipient: RFC822; user at gmail.com
>
> Action: failed
>
> Status: 5.7.1
>
> Remote-MTA: DNS; gmail-smtp-in.l.google.com
>
> Diagnostic-Code: SMTP; 550-5.7.1 [2606:fa00:400:2006:250:56ff:fe92:282a]
> Our system has detected that
>
> Last-Attempt-Date: Fri, 13 Jan 2017 08:19:20 -0500
>
>
>
> --v0DDJKOE005944.1484313560/zendto.XXX.ca
>
>
>
> *From:* zendto-bounces at zend.to [mailto:zendto-bounces at zend.to] *On Behalf
> Of *Mike Brudenell
> *Sent:* Friday, January 13, 2017 9:40 AM
> *To:* ZendTo Users <zendto at zend.to>
> *Subject:* Re: [ZendTo] Issues with sending to external users
>
>
>
> Hi, Brian -
>
>
>
> Firstly note that I've not touched Sendmail since 2008 (we use Exim now)
> so my memory/interpretation might be hazy in places in my comments below…
>
>
>
> On 13 January 2017 at 13:31, Brian Novogradac <
> Brian.Novogradac at utoronto.ca> wrote:
>
> Thanks for helping me out here here is some more information.
>
>
>
> -          Running Centos 6.8
>
> -          Yes the zendto is sending messages to sendmail on the machine
>
> -          I have all hostname information set correctly in hosts file
>
> -          In sendmail.mc I have added the domainname in
> define(`confDOMAIN_NAME', `zendto.host.ca')dnl
>
> I seem to remember that you set confDOMAIN_NAME to the domain name you
> want adding to unqualified addresses — ie, those that are only a username.
> If you have *really* set this to "zendto.host.ca" then a message from/to
> the plain username address
>
>
>
> apache
>
>
>
> say, becomes
>
>
>
> apache at zendto.host.ca
>
>
>
> I've used dig to look up data for the domain "host.ca" and to be honest
> I'm not convinced you've really set it to that as it seems to be something
> to do with domainsatcost.ca.
>
>
>
>
>
> Maillog:
>
>
>
> Jan 13 08:19:19 zendto sendmail[5941]: v0DDJILc005941: from=apache,
> size=1517, class=0, nrcpts=1, msgid=<201701131319.
> v0DDJILc005941 at zendto.XXXXX>, relay=apache at localhost
>
>
>
> The above will be the locally generated message your apache username is
> creating and handing to Sendmail.
>
>
>
>
>
> Jan 13 08:19:19 zendto sendmail[5942]: v0DDJJOE005942: from=<apache@
> zendto.XXXXX >, size=1744, class=0, nrcpts=1, msgid=<201701131319.
> v0DDJILc005941@ zendto.XXXXX >, proto=ESMTP, daemon=MTA,
> relay=localhost.localdomain [127.0.0.1]
>
>
>
> Then sendmail qualifies the plain sender address "apache" with a domain
> name, making it <apache.zendto.XXXXX> — hmm, if that's the case then that
> won't be a valid email address.
>
>
>
> I seem to recall that "relay=" identifies the server the message is
> transmitted onward to: in this case to the SMTP server running on the same
> machine — localhost.localdomain [127.0.0.1]
>
>
>
>
>
> Jan 13 08:19:19 zendto sendmail[5941]: v0DDJILc005941: to=
> userXXX at gmail.com, ctladdr=apache (48/48), delay=00:00:01,
> xdelay=00:00:00, mailer=relay, pri=31517, relay=[127.0.0.1] [127.0.0.1],
> dsn=2.0.0, stat=Sent (v0DDJJOE005942 Message accepted for delivery)
>
>
>
> I think the above is Sendmail logging it has successfully transmitted your
> message to the SMTP listener running on your host.
>
>
>
>
>
> Jan 13 08:19:20 zendto sendmail[5944]: STARTTLS=client, relay=
> gmail-smtp-in.l.google.com., version=TLSv1/SSLv3, verify=FAIL,
> cipher=ECDHE-RSA-AES128-GCM-SHA256, bits=128/128
>
>
>
> Your Sendmail then decides it needs to transmit the message to the server
> gmail-smtp-in.l.google.com
>
>
>
> Which tallies with the MX records for gmail.com — these have the most
> preferred one being gmail-smtp-in.l.google.com
>
>
>
>
>
> Jan 13 08:19:20 zendto sendmail[5944]: v0DDJJOE005942: to=<
> userXXX at gmail.com >, ctladdr=<apache@ zendto.XXXXX > (48/48),
> delay=00:00:01, xdelay=00:00:01, mailer=esmtp, pri=121744, relay=
> gmail-smtp-in.l.google.com. [IPv6:2607:f8b0:4001:c01::1b], dsn=5.0.0,
> stat=Service unavailable
>
>
>
> The above line is Gmail's SMTP server refusing to accept your message,
> returning a 5xx permanent failure response code, with the rather unhelpful
> explanatory text "Service unavailable".
>
>
>
> The 5xx response code tells your Sendmail to abandon any further attempts
> to send the message and to generate a Non-Delivery Report to return to the
> sender.
>
>
>
>
>
> Jan 13 08:19:20 zendto sendmail[5944]: v0DDJJOE005942: v0DDJKOE005944:
> DSN: Service unavailable
>
> Jan 13 08:19:20 zendto sendmail[5944]: v0DDJKOE005944: to=root,
> delay=00:00:00, xdelay=00:00:00, mailer=local, pri=32992, dsn=2.0.0,
> stat=Sent
>
>
>
> This shows a message being delivered to the local mailbox belonging to the
> root username on your server — ie, the Zendto box. Check in that mailbox
> and you'll likely find the Non-Delivery Report, hopefully with some
> information about why the message was rejected by Gmail.
>
>
>
> Things that trouble me are the stray spaces everywhere. For example the
> sender address seems to be <apache@ zendto.XXXXX > and the recipient
> address < userXXX at gmail.com >. But a quick test suggests Gmail would
> reject these with a "555 5.5.2 Syntax error." response rather than "Service
> unavailable".
>
>
>
>
>
> Email Header:
>
>
>
> Received: from zendto.XXXXX (localhost.localdomain [127.0.0.1]) by
> zendto.XXXXX t(8.14.4/8.14.4) with ESMTP id v0CJ8WAd001980; Thu, 12 Jan
> 2017 14:08:32 -0500
> Received: (from apache at localhost) by zendto.XXXXX (8.14.4/8.14.4/Submit)
> id v0CJ8Wm9001976; Thu, 12 Jan 2017 14:08:32 -0500
> Date: Thu, 12 Jan 2017 14:08:32 -0500
> Message-ID: <201701121908.v0CJ8Wm9001976@ zendto.XXXXX
> <201701121908.v0CJ8Wm9001976 at send.utoronto.ca>>
> To: < userXXX at gmail.com >
> Subject: User has dropped off a file for you
> X-PHP-Originating-Script: 0:NSSDropbox.php
> From: Zendto <no-reply@ zendto.XXXXX <no-reply at utoronto.ca>>
>
>
> Basically there's still a lot of obfuscation, possibly along with some
> typos (the stray spaces) introduced whilst obfuscating, for anyone else to
> be sure what's going on. You'll need to discuss your pristine logs with a
> local Sendmail support guru at your site.
>
> Cheers,
>
> Mike B.
>
>
>
> --
>
> Systems Administrator & Change Manager
>
> IT Services, University of York, Heslington, York YO10 5DD, UK
>
> Tel: +44-(0)1904-323811 <01904%20323811>
>
>
>
> Web:                www.york.ac.uk/it-services
>
> Disclaimer:      www.york.ac.uk/docs/disclaimer/email.htm
>
> _______________________________________________
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> ZendTo at zend.to
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>

-- 
Systems Administrator & Change Manager
IT Services, University of York, Heslington, York YO10 5DD, UK
Tel: +44-(0)1904-323811

Web: www.york.ac.uk/it-services
Disclaimer: www.york.ac.uk/docs/disclaimer/email.htm
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