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False rejection of valid sender domain

Gandalf
Community Gaffer
Community Gaffer
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Registered: ‎21-04-2017

Re: False rejection of valid sender domain

Ah thanks for the clarification @MJN 

Fingers crossed it's not a regular occurrence, but let us know if you do see this happen frequently.

From 31st October 2022, I no longer have a regular presence here as I’ve moved on to a new role.
Anoush Mortazavi
Plusnet
VileReynard
Hero
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Registered: ‎01-09-2007

Re: False rejection of valid sender domain

I'm getting emails from Plusnet community which fail DMARC, but pass DKIM & SPF - these give warnings that:-

 

This email has failed its domain's authentication requirements. It may be spoofed or improperly forwarded!

"In The Beginning Was The Word, And The Word Was Aardvark."

MJN
Pro
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Re: False rejection of valid sender domain

That's a different issue as in my case it is outgoing mail that is being rejected.

Incidentally, what do you mean by 'fail DMARC'? DMARC isn't a test itself; it is merely a method of instructing what to do if both the DKIM and SPF tests fail... But you say both of these are passing?

VileReynard
Hero
Posts: 12,616
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Re: False rejection of valid sender domain

I'll just mention that I'm getting headers of (in part) 

Authentication-Results: mailin004.protonmail.ch; dmarc=fail (p=none dis=none)
 header.from=plus.net
Authentication-Results: mailin004.protonmail.ch; spf=pass
 smtp.mailfrom=bounces+13614266-3fb6-jeremyboden=protonmail.com@em7732.eu.khoros-mail.com
Authentication-Results: mailin004.protonmail.ch; dkim=pass (1024-bit key)
 header.d=eu.khoros-mail.com header.i=@eu.khoros-mail.com header.b="JtntkXSb"

Since its off-topic I'll leave it for now, especially as its just a minor irritation.

"In The Beginning Was The Word, And The Word Was Aardvark."

MJN
Pro
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Re: False rejection of valid sender domain

A check for the DMARC policy for eu.khoros-mail.com will always fail as there's no DMARC record for it:

$ host -t txt _dmarc.eu.khoros-mail.com
Host _dmarc.eu.khoros-mail.com not found: 3(NXDOMAIN)

To be honest I'm not sure why that would lead to a warning of potential spoofing though, particularly given that the SPF and DKIM tests are passing. One to raise with Protonmail given that it is they that are performing the check.

rickeveleigh
Dabbler
Posts: 10
Registered: ‎09-08-2019

Re: False rejection of valid sender domain

I'm seeing the same thing. Have had it over the last few months for one valid domain and now today to a different domain that has not given an error before. Could you ask NetOps to check please?

Your message did not reach some or all of the intended recipients.

      Subject:  <redacted>

      Sent:     13/01/2020 13:16

The following recipient(s) cannot be reached:

      '<redacted>' on 13/01/2020 13:17

            Server error: '550 <<redacted>@nexus-resources.co.uk> recipient rejected - domain has no delivery address (DNS MX or A record)'

      '<redacted>@nexus-resources.co.uk' on 13/01/2020 13:17

            Server error: '550 <<redacted>@nexus-resources.co.uk> recipient rejected - domain has no delivery address (DNS MX or A record)'

MJN
Pro
Posts: 1,318
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Registered: ‎26-08-2010

Re: False rejection of valid sender domain

That's a slightly different issue as the rejection is against the destination address. Might be a common cause though if the mail servers are suffering intermittent DNS lookup failures.
rickeveleigh
Dabbler
Posts: 10
Registered: ‎09-08-2019

Re: False rejection of valid sender domain

Yes, occasional DNS failures is what it seems like -- the other domain had the same message and they are addresses we send to regularly. Others sending to them (not from Plusnet) have no issues.

BD
Plusnet Alumni (retired)
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Registered: ‎24-04-2017

Re: False rejection of valid sender domain

Hi @rickeveleigh, I'm sorry to hear you've also seen bounce backs as of recent. Can I ask how often this occurs?

rickeveleigh
Dabbler
Posts: 10
Registered: ‎09-08-2019

Re: False rejection of valid sender domain

It's occasional, but frequent enough to be frustrating.

Gandalf
Community Gaffer
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Re: False rejection of valid sender domain

Hi @rickeveleigh Could you PM me the full bounce back you get, the email address you're sending from as well the address you're attempting to send to so I can raise this for investigation? Also how often does this occur?

[edit]

With regards to how often it occurs for example how many out of x number of emails you send are rejected due to this error?

From 31st October 2022, I no longer have a regular presence here as I’ve moved on to a new role.
Anoush Mortazavi
Plusnet