How to reliably SMTP or free smtp mail relay service?

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ageorge

428 posts

Ultimate Geek

#272293 18-Jun-2020 11:18

Hi Im not sure this is the right forum.

Im a slingshot customer and use their (what I would call) passthrough smtp relay.

Settings used with Thunderbird are smtp.slingshot.co.nz 587 STARTTLS no authentication. Which allows me to send from any email address normally.

This mostly works fine except occasionally and for some unknown reason I get bounced emails eg:

Diagnostic-Code: smtp; 550 permanent failure for one or more recipients (customer.care@pulseenergy.co.nz:blocked)

No matter what originator (I have several emails) the bounce would be consistent with the above until I changed SMTP settings/outgoing server eg to my gmail account.

So I did a search for free smtp provider and end up with SendinBlue and several others which are designed for mass emails.

I dont like to use gmail as relay as its slow and often modifies the originator email address to my gmail one (another wee problem).

I just want a reliable relay service without all the bells and whistles that lets me use any email originator address; any suggestions?

Thanks, Al.

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693 posts

Ultimate Geek

#2507201 18-Jun-2020 11:21

SMTP2GO is good. Not free though.

Amanon

ageorge

428 posts

Ultimate Geek

#2507202 18-Jun-2020 11:23

Dulouz:

SMTP2GO is good. Not free though.

Yes, Im pretty sure thats the same as SendinBlue though; not what I want Im just a PC user, not mass mail.

SirHumphreyAppleby

1328 posts

Uber Geek

#2507209 18-Jun-2020 11:29

Dulouz: SMTP2GO is good. Not free though.

They offer a free plan that includes 1,000 e-mails per month.

I recommend it to users of my software because of the simple price structure. GMail won't be an option as they are disabling what Google likes to call "less secure apps" in the near future (the future of "App passwords" is less clear), so unless your software supports OAuth, you'll want to switch to another provider.

danielfaulknor

660 posts

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#2507210 18-Jun-2020 11:30

There's nothing stopping you from signing up to somewhere like SMTP2GO, Mailgun, Postmark etc and verifying your domain and then adding the SMTP credentials to Thunderbird. It's probably going to be the simplest path for you I think.

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ageorge

428 posts

Ultimate Geek

#2507253 18-Jun-2020 11:32

SirHumphreyAppleby:

Dulouz: SMTP2GO is good. Not free though.

They offer a free plan that includes 1,000 e-mails per month.

I recommend it to users of my software because of the simple price structure. GMail won't be an option as they are disabling what Google likes to call "less secure apps" in the near future (the future of "App passwords" is less clear), so unless your software supports OAuth, you'll want to switch to another provider.

So they provide a free email relay for multiple domains eg I have originator addresses of msn.com zoho.com gmail.com and so on; all I want is similar to what I have been using slingshot as server but with more reliability of delivery, using thunderbird as client, and the originator email address remains.

ageorge

428 posts

Ultimate Geek

#2507260 18-Jun-2020 11:35

danielfaulknor:

There's nothing stopping you from signing up to somewhere like SMTP2GO, Mailgun, Postmark etc and verifying your domain and then adding the SMTP credentials to Thunderbird. It's probably going to be the simplest path for you I think.

Well I did that with SendinBlue and then there seemed not place to get smtp credentials; perhaps I didnt look hard enough?

danielfaulknor

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#2507262 18-Jun-2020 11:37

ageorge:

msn.com zoho.com gmail.com and so on;

I assumed you were talking about your own domain name here.

You may be able to verify these domains on those services (some of them send you an email to verify you can email as them) but you will need to check what the Return-Path is being set to so that you don't run afoul of SPF. For example, Postmark has the sender address and reply-to address set to your from address, but the Return-Path address is them - https://postmarkapp.com/support/article/1092-how-do-i-set-up-spf-for-postmark

You may still find however that emails from those big providers, sent to other users at those big providers, will get marked as spam as they expect all email from their own domain to come from their mail servers.

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danielfaulknor

660 posts

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#2507263 18-Jun-2020 11:38

ageorge:

danielfaulknor:

There's nothing stopping you from signing up to somewhere like SMTP2GO, Mailgun, Postmark etc and verifying your domain and then adding the SMTP credentials to Thunderbird. It's probably going to be the simplest path for you I think.

Well I did that with SendinBlue and then there seemed not place to get smtp credentials; perhaps I didnt look hard enough?

It looks like you need to be signed up with their transactional service, rather than bulk service. Link below..

https://help.sendinblue.com/hc/en-us/articles/209462765-What-is-SendinBlue-SMTP-

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ageorge

428 posts

Ultimate Geek

#2507269 18-Jun-2020 11:56

Hi I was just going through the process with SendinBlue again; they provide SMTP relay details, but then you have to activate by sending them another email requesting transactional smtp service which Ive done.

Will let you know how it goes. Meanwhile back to slingshot smtp.

I must say, slingshot has been a good service except for their flakey NFV18ACV modem not suitable for wifi; Ethernet fine, had to buy my own wifi router to sort issues out.

SirHumphreyAppleby

1328 posts

Uber Geek

#2507284 18-Jun-2020 12:20

ageorge:

So they provide a free email relay for multiple domains eg I have originator addresses of msn.com zoho.com gmail.com and so on; all I want is similar to what I have been using slingshot as server but with more reliability of delivery, using thunderbird as client, and the originator email address remains.

There is a setting in SMTP2Go that can be used to restrict senders to specific domains or addresses. If that's off, you should be fine*.

SMTP2Go logs confirm the mail below was delivered to GMail.

* Subject to domain SPF rules and spam filter stupidity.

>cmail -host:*****:*****@mail.smtp2go.com:2525 -from:*****@orcon.net.nz -to:*****@gmail.com "-subject:Test message" "-body:It rubs the lotion on its skin or else it gets the hose again." -d -authtypes:PLAIN
< 220 mail.smtp2go.com ESMTP Exim 4.92-S2G Thu, 18 Jun 2020 00:13:41 +0000
> ehlo [10.0.0.101]
< 250-mail.smtp2go.com Hello [10.0.0.101] [x.x.x.x]
< 250-SIZE 52428800
< 250-8BITMIME
< 250-DSN
< 250-PIPELINING
< 250-AUTH CRAM-MD5 PLAIN LOGIN
< 250-CHUNKING
< 250-STARTTLS
< 250-PRDR
< 250 HELP
> auth plain ************************************************
< 235 Authentication succeeded
> mail from:<*****@orcon.net.nz>
< 250 OK
> rcpt to:<*****@gmail.com>
< 250 Accepted <*****@gmail.com>
> data
< 354 Enter message, ending with "." on a line by itself
> Date: Thu, 18 Jun 2020 00:12:35 GMT
> Subject: Test message
> From: "*****@orcon.net.nz" <*****@orcon.net.nz>
> To: "*****@gmail.com" <*****@gmail.com>
> Message-ID: <4Gs7xAEAwZ12bfHP@orcon.net.nz>
> X-Mailer: CMail 0.8.0 amd64 (https://www.inveigle.net)
>
> It rubs the lotion on its skin or else it gets the hose again.
> .
< 250 OK id=1jliBZ-WfZZGb-Nb
> quit
< 221 mail.smtp2go.com closing connection

richms

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#2507308 18-Jun-2020 12:54

What email address are you using where they do not provide a SMTP server to send out from that will have all the correct records in place to actually get delivered? Seems weird to be using one from your ISP these days.

Richard rich.ms

1101

2195 posts

Uber Geek

#2507309 18-Jun-2020 12:55

As painfull as it will seem,
want reliable email, then move away from ISP provided email service .

Start another gmail our outlook.com a/c (or 365 if its a domain email adress). Forward all slingshot emails to that new gmail a/c

.. rather than bandage up the slingshot issues and have possibly more issues later on .

ageorge

428 posts

Ultimate Geek

#2507435 18-Jun-2020 13:42

Well I tried SendinBlue/waiting for them to enable smtp - too long to wait; otherwise appears to be good service.

smtp.sendgrid.net/convoluted settings screen. help not clear. smtp finally configured only to get this error message: An error occurred while sending mail. The mail server responded: The from address does not match a verified Sender Identity. Mail cannot be sent until this error is resolved. Visit https://sendgrid.com/docs/for-developers/sending-email/sender-identity/ to see the Sender Identity requirements. Please check the message and try again.

smtp2go; yes, appears the perfect solution. easy as to set up, in the clear smtp instructions (other 2 setup smtp hidden in help)

Thanks for suggestion guys.

Al.

jarledb

Webhead
2518 posts

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#2507611 18-Jun-2020 17:18

Have I misunderstood, or are you trying to send via a third party SMTP with gmail.com and outlook/msn/hotmail.com etc. email addresses?

Those use strict SPF records that only allow emails to be sent via their servers. So if you are trying to use an @gmail.com address through any other SMTP service than Googles, the mail servers you are sending to will see that that server is not allowed to send gmail.com email.

The reason it works some places is that those email servers are not checking SPF, which seems like a really bad way to go these days.

So in short: For any email through Microsoft Hotmail (Outlook.com, Hotmail etc), and through Googles Gmail (and really any other such email service) is not going to work well via third party SMTP servers.

It is only for your own domains that you will have any luck using third party SMTP servers, given you set up SPF and other spam fighting measures correctly.

danielfaulknor

660 posts

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#2507613 18-Jun-2020 17:22

jarledb:

Have I misunderstood, or are you trying to send via a third party SMTP with gmail.com and outlook/msn/hotmail.com etc. email addresses?

Those use strict SPF records that only allow emails to be sent via their servers. So if you are trying to use an @gmail.com address through any other SMTP service than Googles, the mail servers you are sending to will see that that server is not allowed to send gmail.com email.

The reason it works some places is that those email servers are not checking SPF, which seems like a really bad way to go these days.

So in short: For any email through Microsoft Hotmail (Outlook.com, Hotmail etc), and through Googles Gmail (and really any other such email service) is not going to work well via third party SMTP servers.

It is only for your own domains that you will have any luck using third party SMTP servers, given you set up SPF and other spam fighting measures correctly.

This is no longer the case. Check out my answer and the corresponding link above - https://postmarkapp.com/support/article/1092-how-do-i-set-up-spf-for-postmark

TL;DR the Return-Path is the important bit, so you can still display a different email address. I haven't tested it myself but from comments above it seems to work with SMTP2GO

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