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Mail delivery to recipients taking 5hrs plus

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Re: Plusnet to Gmail addresses - what's the problem?


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Superuser
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Re: Plusnet to Gmail addresses - what's the problem?

@PeterB1 wrote:

3) Will trying to mitigate the effect on this group of users still mean a lengthy delay before the fix is implemented?

Trying to mitigate the effects has already started. I'd take a guess at any delay in implementing the fix would depend on how they get on with that compared with how long the fix takes to prepare.

I tried re-setting the outgoing server to (ironically enough!) Google's SMTP server (smtp.gmail.com) which worked fine. Are you saying that, when SPF records have been added, smtp.gmail.com will no,longer work as a back-up?

That won't have worked for quite some time now (couple of years maybe?).  You can only send mail through smtp.gmail.com from addresses registered with them.  For example if I try to send an email from peter@domain.com whilst I've authenticated with their smtp server as phil@domain.com, then the email received will come from phil@domain.com

 

Superuser
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Re: Plusnet to Gmail addresses - what's the problem?

To add to Phil's responses...


@PeterB1 wrote:

1) Do we know roughly when "in the New Year" the adding of SPF records will occur?

"We" the superusers know as much as everyone else on the time line - it would be unwise for this to happen before the consequences for the user base are significantly mitigated.

2) Will this fix still adversely affect the group of users PlusNet has identified as at risk when a fix is implemented?

If the at risk users have not implemented the published mitigations they will find that from for some target email services, email sent by SMTPs not belonging to Plusnet will not be accepted for delivery.

3) Will trying to mitigate the effect on this group of users still mean a lengthy delay before the fix is implemented?

See (1) above - there are 3 essential steps which need to be completed before this can be switched on.

4) Do you think adding SPF records will actually eliminate delays in emails sent to Gmail? (I ask because PlusNet representatives earlier talked vaguely about an unspecified possible fix which might work - but didn't sound overly confident about it. Is this the same fix they had in mind then?

This is indeed at the heart of the matter - Google has refused to engage in discussion on this topic.  Looking at their help on such matters only points in the direction of "bulk email senders" which of course individual Plusnet users are not.  One therefore has to start guessing - the current guess is that Gmail cannot discern the difference between myaccount.plus.com and youraccount.plus.com so it treats *.plus.com as being the one and same as plus.com - if this is in fact what is happening them SPF may solve the issue.  At this stage it can be nothing more than a diagnostic elimination of non-essential (albeit desirable) spam mitigation options.  There are a couple of other non-essential options which could yet have a hand in Gmail's unilateral non-complaint actions.

Finally, on the point about configuring SMTP servers: my PC, iPad and iPhone all currently use relay.plus.net to send emails from my PlusNet address, so I should be OK there. However, occasionally in years gone by I have had trouble getting relay.plus.net to work when I'm abroad. On some of those occasions, I tried re-setting the outgoing server to (ironically enough!) Google's SMTP server (smtp.gmail.com) which worked fine. Are you saying that, when SPF records have been added, smtp.gmail.com will no,longer work as a back-up?


Building on Phil's reply here - after this is implemented, it will not be possible to send emails to a good number of recipients from @myaccount.plus.com if not sent via relay.plus.net - it is not just a matter that smtp.gmail.com will no longer work (setting aside Phil's comment about recent changes) NO OTHER SMTP server will work for many inbound serves either.

The usual cause of not being able to use relay.plus.net is either it not being configured for authenticated access or it being configured on port 25 - technically that port is for MTA to MTA message relay.  Message submission (as from an email client to a MTA) should be on port 587.  Some networks block access to port 25 on servers not on that network as an anti-spam measure.

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Re: Plusnet to Gmail addresses - what's the problem?


@PeterB1 wrote:

1) Do we know roughly when "in the New Year" the adding of SPF records will occur?

We have no dates at the moment, it requires some dependent work to be completed first before we can start.

2) Will this fix still adversely affect the group of users PlusNet has identified as at risk when a fix is implemented?

It's not really a fix, it should resolve the issue but SPF records are not a requirement and emails can be sent without delay to almost anywhere else but to answer your question yes, anyone not using our outbound mail server runs the risk of the mail being rejected by the recipient's provider

3) Will trying to mitigate the effect on this group of users still mean a lengthy delay before the fix is implemented?

The problem is we don't know who exactly who isn't using our outbound servers because we don't know how you've configured your client. Historically though customers who left us were placed on products that denied access to our outgoing mail servers. Even if they rejoined us it was impossible to transfer the mail component to the new account.

These customers, to continue to send mail would currently need to use a different outgoing mail server and we can identify these people and are looking at plans to contact them.

Even if we had no impacted customers we'd still need the dependant engineering work to be completed.

 

4) Do you think adding SPF records will actually eliminate delays in emails sent to Gmail? (I ask because PlusNet representatives earlier talked vaguely about an unspecified possible fix which might work - but didn't sound overly confident about it. Is this the same fix they had in mind then?

In testing, it's worked well but as we don't own googles servers we can't definitively say it will resolve anything, the only way to really tell for certain is to deploy it and monitor it.

 

Finally, on the point about configuring SMTP servers: my PC, iPad and iPhone all currently use relay.plus.net to send emails from my PlusNet address, so I should be OK there. However, occasionally in years gone by I have had trouble getting relay.plus.net to work when I'm abroad.

If the recipient's email provider uses SPF then it's my understanding that the email would likely be refused.

 Jono H
 Plusnet Community Manager
PeterB1
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Re: Plusnet to Gmail addresses - what's the problem?

Many thanks (again!) JonoH for your swift response - and the valuable information you've given us.

Like many PlusNet customers probably, I'm a long-time user of today's technology, but I'm not always up to speed with what happens 'under the bonnet'.

Having researched  what SPF records are and how they work - and with the benefit of your new information - I now understand what the problem is regarding previous customers who've migrated from PlusNet while taking their email addresses with them.

 Two further questions:

1) To a layman, it sounds as if SPF might be a clever way of resisting spammers. Is there a downside to it (apart from the burden of work involved) to explain why PlusNet hasn't chosen to use it in the past?

2) Does it make sense to you that sometimes in the past I've had problems sending emails via relay.plus.net from my PlusNet account when I'm abroad?  (I mainly travel in Europe and the USA.)  What might cause this to happen?

Superuser
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Re: Plusnet to Gmail addresses - what's the problem?

Does it make sense to you that sometimes in the past I've had problems sending emails via relay.plus.net from my PlusNet account when I'm abroad?  (I mainly travel in Europe and the USA.)  What might cause this to happen?

@PeterB1 for the last few years I've spent a number of weeks in Portugal over the winter and have VERY VERY occasionally had problems sending via relay.plus.net and they've been temporary. I'm pretty sure that I've only ever seen issues when on Mobile networks and I've put it down to the IP I was on being 'blacklisted' in some way. You will have problems with some networks using port 25 but 587 should work fine. Last couple of years the apartment we rent has had a fixed Broadband connection and I've not seen any problems sending via that at all.

There is a much lower threshold as to volume of mail you can send over a short period when authenticated on a non-PN network though, so if you send lot's of email then you might get caught out with that.

Superuser
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Re: Plusnet to Gmail addresses - what's the problem?

Hi Peter,

  1. Yes there are potential "down-stream" issues consequential to implementing SPF which would be way outside the scope of an ISP implementing SPF to mitigate: If a sending address has a SPF record and the receiving address is a forwarding address and the forwarding service does not implement SRS then the end recipient might reject the email as not coming from the SPF defined SMTP - it is very complex!!  IIRC Plusnet attempted to implement the in-bound side** of SPF and ran foul of this big time.
  2. I alluded to this in my reply, maybe I was not overly clear - network management is a complex beast - some networks apply more stringent rules than others and user's set up of software is not as stringent as it might be.  To be pedantically correct, email clients should never submit email on port 25 of the SMTP server … the fact that it largely works results in in being accepted as the common default.  The correct port is 587.  Some networks will not permit connection to port 25 for "off network" servers.  For example, you might well be able to connect to relay.plus.net:25 when connected to the Plusnet network, but not when connected via Bell Atlantic, whereas relay.plus.net:587 should always work.

** There are two sides to SPF...

  1. Implementing rules for which SMTP server is permitted to send email on behalf of an email domain - this needs TXT records inserting into the DNS name server for that domain.  You could think this as being the "outbound" side - specified SMTP servers are considered to be valid senders, all others are not.
  2. Checking conformity of the rules for emails received from an email domain - this requires the accepting MTA to look up the SPF TXT DNS record for the domain and verify that the email came from a permitted SMTP server.  You could think of this as being the "inbound" side - did this email come from a permitted SMTP server for this sender?

On the last point consider...

  • A sends an email to B where A has a SPF constraint
  • B chooses to forward emails to C

With simple straight forward forwarding, C will see the email sent by A as having come from B and therefore the SPF compliance will fail.

For the above to function without additional issues the man in the middle B needs to implement something called SRS so that it is clear to C that the email has been forwarded and should be considered as having been sent by A using A's SMTP (or something to that effect).

There is also the message return path to consider in this scenario.  If C finds an issue, it replies to B … who forwards the message to C!!  Again SRS facilitates A as being the return path addressee.

 

It is all very complex and given the potential spillage to issues elsewhere outside of the control of an individual ISP would be best left alone … Google being the big powerful organisation which they are … have decided to make that both impossible and arduous for other email suppliers.

HTH - sorry if it seems complex … but that is exactly what it is!

stumped
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Re: Plusnet to Gmail addresses - what's the problem?

Has some part of this fix already been implemented?   Because I am randomly unable to send emails when connected via VPN -if I  exit VPN the send goes through immediately and without problem - sounds awfully like the kind of thing that SPF would cause? 

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Re: Plusnet to Gmail addresses - what's the problem?

The connection you are on has no bearing on spf if you are sending through pn relay - it’s that info which is in the spf record.

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Superuser
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Re: Plusnet to Gmail addresses - what's the problem?

Sending and delivering are not directly connected, they are very distinct. This is nothing like what SPF would cause.

SPF has nothing to do with sending, it is a factor which if present, might be applied when considering the acceptance of an attempt to deliver.

I would suspect that your smtp connection is configured to use port 25 not 587. It would be helpful to take this into a separate topic.
stumped
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Re: Plusnet to Gmail addresses - what's the problem?

No, it's on 587 (on relay.force9.net, as I am a customer from the old F9 days).  I'll monitor it and raise on a separate thread if it keeps recurring.

PeterB1
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Re: Plusnet to Gmail addresses - what's the problem?

There was some useful information on this thread recently about how, when the fix for the Gmail delay problem is eventually implemented, it will be essential for customers with a PlusNet email account to use the SMTP server relay.plus.net. I remarked at the time that I have occasionally had problems using relay.plus.net when I'm abroad. In the last couple of days I have had the same problem here in the UK when connected to public wifi - once in a hotel and once at a racecourse.  The wifi signal in both places was strong and I had no problem browsing the web, but when I tried to send emails from my iPhone using relay.plus.net, the outgoing emails failed to deliver and I got an error message to the effect that the phone could not connect to relay.plus.net. Eventually, I switched off my phone's connection to the local wifi and the emails were immediately sent successfully using the phone network (in my case Vodafone).  On many other occasions in the UK and abroad I have successfully sent emails using a local public wifi, so I'm guessing the problem is that PlusNet's server, for some reason, blocks emails from some wifi networks and not others. When the Gmail fix is implemented and I have no choice but to use relay.plus.net, this could become quite an issue. Using the phone network in the UK is OK as a workaround (assuming there is a phone signal at the relevant location) but it isn't when I'm abroad because of the cost. Can anyone from PlusNet or from among PlusNets expert users offer any explanation and advice?

Plusnet Help Team
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Re: Plusnet to Gmail addresses - what's the problem?

Hi @PeterB1,

 

Thanks for getting in touch.

 

A lot of wifi hotspots block port 25 which is the outgoing mail server port. More info on that here - I can only assume that this was the case when you were experiencing issues within the UK. If this happens again, could you try to send an email through the webmail service that's attached to our website and see if the problem persists? If it works, that would verify my theory as only your mail client would try to use that port rather than webmail. 

 

Best wishes

 

Dave

 

 

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 Dave G
 Plusnet Help Team
JHA1E
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Re: Plusnet to Gmail addresses - what's the problem?

This may or may not be helpful. I always set my outgoing server settings to require authentication  (SMTP) and use my User Name and password to authenticate. Port 587 is used. This has worked on every occasion.

PeterB1
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Re: Plusnet to Gmail addresses - what's the problem?

Forgive my ignorance, but I use a PC at home and both iPad and iPhone 8 (through the Mail app) on POP3 when away from home.

(1) How exactly do I check what the current port setting is - and change it if necessary?

2) Would I need to change it once - or three times for the different devices?