Message Delivery Failure - Anyone else having problems?

[licquorice]

But if you are sending using BT's SMTP server you have to authenticate with a BTinternet email address which presumably will be considered as the sending domain regardless of the actual sending address.

With no SPF record at all, sending via BT's SMTP server resulted in an SPF pass received at a Gmail address. When I sent  via IONOS SMTP server to a BT internet address the mail wasn't received, but was when SPF record for IONOS server was added . Just realised I didn't check sending to Gmail address without SPF record from IONOS server, will try that later (got a Zoom meeting shortly)

[Roger1945]

I think there may be 2 separate cases for sending mail. You can either specify sending address (from BT) as your native BT one (xxx@btinternet.com) or you can give your domain name as the Sender (xxx@your domain name). Obviously the sending server will treat these differently.

I used to send using my 123.reg address as the Sender using BT, so that receivers would see (and auto reply to) my domain address. However, after getting multiple failures, 18 months or so ago, I changed to always sending using my BT address as Sender and including my domain name address as the Reply To address. This seems to work OK, although I have not done any rigorous testing.

Could this difference in Sender address account for the differing views on the relevance SPF etc. for sending email from BT?

[licquorice]

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@Roger1945 wrote:

Could this difference in Sender address account for the differing views on the relevance SPF etc. for sending email from BT?

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Quite possibly.

One of the reasons I always use the native SMTP server for whatever address I am sending from.

[licquorice]

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@licquorice wrote:

But if you are sending using BT's SMTP server you have to authenticate with a BTinternet email address which presumably will be considered as the sending domain regardless of the actual sending address.

With no SPF record at all, sending via BT's SMTP server resulted in an SPF pass received at a Gmail address. When I sent  via IONOS SMTP server to a BT internet address the mail wasn't received, but was when SPF record for IONOS server was added . Just realised I didn't check sending to Gmail address without SPF record from IONOS server, will try that later (got a Zoom meeting shortly)

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Sending from IONOS server without SPF record resulted in SPF neutral rather than Pass so I guess Gmail is more relaxed about lack of SPF record than BT.

[IanMK13]

@licquorice 

Gmail appears to be quite helpful in explaining its SPF decision. If I have a <mydomain> SPF with an ip4 address specifying BT SMTP servers then I see the following:

   google.com: domain of <email@mydomain> designates <BT_SMTP_server_IP> as permitted sender

In your first case (no mydomain SPF record, from mydomain address via BT SMTP servers) how does it explain the pass?

(PS. I've not received any DMARC reports so far so I'm no further forward in knowing whether I've configured my DMARC policy correctly.  I suspect that I may be losing some outgoing emails - I have had one or two people claim not to have received emails from me.)

[licquorice]

@IanMK13  This is only guessing, but I as I said in message 181, I think it is because you are authenticating on the BT SMTP server using a BTinternet address.

Try sending without the BTinternet details in your SPF record and see if you still get a pass.

All my testing has been carried out using MS Outlook 2010

[IanMK13]

@licquorice 

I've tried sending from an address with no SPF record via BT SMTP servers to Gmail but I get an SPF fail with a failure description along the lines of :

    google.com: domain of <email@mydomain> does not designate <BT_SMTP_server_IP> as permitted sender

where BT_SMTP_server_IP> is the IP address of the btinternet.com server (which was in the range that I entered previously - apparently successfully - in a different domain SPF record) passing the message into the mx.google.com domain. This is what I would have expected and may suggest that I don't need an 'Include:btinternet.com' statement in my SPF record.

As much as I'd like to get to the bottom of this in order to give me confidence in my outgoing emails, I think I may have to let this pass for now. At least the original problem of incoming emails seems to have been resolved. Perhaps I should be more concerned that 123-reg is on a UCEPROTECTL3 blacklist 😮

[licquorice]

@IanMK13 

Perhaps I didn't leave it long enough yesterday for the DNS records to propagate with the BTinternet info missing in the SPF record. Just tried it again now and I get the same as you, so it would appear that it is necessary to include BTinternet servers IP address range in the SPF record. I will re-enter BTinternet details in my SPF record  and try again tomorrow after giving time for the DNS servers to update.

[kinharry]

As far as i'm concerned the problem is sorted. I have done nothing, the last failure message was on Friday and as far as i can see all my messages are getting to me. It would be nice to know how it was fixed but i guess BT or 123 made a change around the 18th April and then backed it out last Friday, No doubt neither will admit it.

[PB-in-devon]

Same for me kinharry.....life continues to be a great mystery!