421 Too Many Messages (1.5.6.2)

Reason: Remote host said: 421 Too many messages
Failed Recipient:******@btinternet.com
Reason: Remote host said: 421 Too many messages (1.5.6.2)

BT, British Telecom, BTinternet are up to their old games again.

A long time ago, in a galaxy far far away they ruffled a few feathers with email with an attempt to get a head start on the (lack of) Net Neutrality gig. I seem to recall it was at best delayed transit, at worse a bounce back with a 4xx (curiously – as that usually means still being tried) in the message body… if you examined the headers there was a message to the effect of “You are sending a lot of mail. If you would like a priority service, then contact X for pricing” … oh – really – errr – no. Name and shame.

I digress: Back to this weeks presentation 421 Too many messages (1.5.6.2) when sending to btinternet.com addresses. My point being – along with the winning that was the short live Phorm (ewww) – they are under the impression they are large enough to bend the rules a little… after all – what are standards or privacy considerations in this day and age. *mutter*

Contacting the postmaster@ we are getting responses to the extent that this is SPF related.

As an engineer at an ISP – I can assure you that this is not SPF related – as there are domains sending that do have that set – yet are experiencing the same issue.

Also – a 4xx should not be a terminal event. It is not a positive rejection (a 5xx SMTP code) – it is a ‘try again later’ … so these are either working their way through the retries and failing on time – or there is something going on that I am missing. It’s wrong either way.

Regretfully – I believe the answer lays in the 1.5.6.2 code there – although I cannot find anywhere obvious on their site regarding this error code. That is going to marry up nicely with a router or ACL code

I have a nasty feeling they may be reverting to type in the fact that we are being seen as sending too many emails. That kind of thing is going to happen if you are an ISP. No surprises there. Nose clean in blacklists (Spamhaus, Barracuda), and reputation (Senderbase) – so what gives… are we heading back to an era where you are expected to know that there is an opt in for a bulk sender? Let’s hope not.

Since we are seeing similar with third party screening vendors this is not personal – and I am guessing it is a much wider issue.

Are you seeing it – or is this news to you?

If I hear anything back from BT postmaster regarding this I will update… with a bit of luck they are either just experiencing an issue – that they will notice and fix – OR – they are trialling something that is going horribly wrong – and with a bit of luck wont last. However – one way or another – you are not alone.

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