topic Re: SMTP Authentication in Email

SMTP Authentication

mbeenham — Fri, 11 Oct 2024 12:08:46 GMT

I am currently in Spain and over the last few days sending emails is failing authentication:

S: 535 ...authentication rejected as source IP has a poor reputation

Current IP address is

185.103.149.175

Is it worth reporting this to PN (will I get a useful response?)

Re: SMTP Authentication

jab1 — Fri, 11 Oct 2024 12:14:59 GMT

It is pointless reporting to PN - it means the connection you are currently using has been abused recently and has therefore been blocked. Is this a mobile one, or fixed?

Re: SMTP Authentication

mbeenham — Fri, 11 Oct 2024 12:39:12 GMT

Thanks for confirming my thoughts.

Its a FTTP connection so maybe I'll try powering off the router for a few hours and see if I et a different IP address.

Re: SMTP Authentication

Townman — Fri, 11 Oct 2024 21:17:31 GMT

This is part of the service reputation preservation mechanisms. You could try using a VPN service which has an exit point in the U.K. Alternatively you could use webmail for sending emails.

Re: SMTP Authentication

mbeenham — Sat, 12 Oct 2024 09:57:17 GMT

It is easier for me just to abandon sending via my PN email for now and use my Hotmail or Gmail SMTP until normal SMTP service from PN is resumed. At least receiving email via my PN POP3 account is not affected.

I use a Thunderbird mail client and webmail is too tedious.

A VPN seems unnecessary for this purpose, though I have used it when on shared networks.

Thanks for the comments though.

Re: SMTP Authentication

jab1 — Sat, 12 Oct 2024 10:02:48 GMT

until normal SMTP service from PN is resumed.

Despite your current blaming of PN, it is not their fault your current IP is regarded as unsafe - it is the fault of whoever misused it previously.

Re: SMTP Authentication

paul_blitz — Sat, 12 Oct 2024 11:29:30 GMT

It CAN be PlusNet's fault: recently my brother was unable to send email vial PlusNet's SMTP... from his own home - PlusNet provided - broadband! It seems that his IP had been blacklisted by Spamhaus and others, and despite it being one of Plusnet's own, it got blocked!

Re: SMTP Authentication

jab1 — Sat, 12 Oct 2024 11:41:04 GMT

@paul_blitz I think I understand what you are trying to say there, but, as I (and others) have tried to explain, it is a users fault for misusing the service, not the suppliers or providing it.

Re: SMTP Authentication

Townman — Sat, 12 Oct 2024 11:42:41 GMT

It does not matter who owns the IP if it gets marked as suspect, it will get quarantined, usually for 24-48 hours.

The ISP is not responsible for the abuse, but rather (in the case of a dynamic IP address) it is down to a previous user. In the context being discussed, the service being abused need not be one provided by the ISP: the abuse of any service which has a high level of protection and reporting, could cause Plusnet's SMTP servers not to accept connections.

Yes it can be inconvenient to individuals ... but better that than the whole of the Plusnet mail service being laid vulnerable to abuse and thereby no mail service accepting outbound emails from Plusnet's servers for all users.

Sadly it is more often foreign 'players' who most seek to abuse SMTP servers, hence the high level of diligence applied to such inbound connections.

Re: SMTP Authentication

Dan_the_Van — Sat, 12 Oct 2024 12:06:56 GMT

@mbeenham wrote:

I am currently in Spain and over the last few days sending emails is failing authentication:

S: 535 ...authentication rejected as source IP has a poor reputation

Current IP address is

185.103.149.175

some details here https://check.spamhaus.org/results?query=185.103.149.175

HTH

Edit: Click on More Info

Re: SMTP Authentication

paul_blitz — Sat, 12 Oct 2024 16:14:48 GMT

If you are sending email from your own personal domain, and can set up a couple of extra DNS records, then you can use someone like MailJet to send your mail. Because you do a 'more secure authentication' with them so that they are 100% sure it's you, they don't block based on source IP address. In fact, I set my brother up to do that when he was blocked by plusnet.

(Unfortunately, if you use a native Plusnet email address, this won't work for you.)

Re: SMTP Authentication

mbeenham — Sat, 12 Oct 2024 17:53:10 GMT

Thank you.

This is the best reply to my original question and if PN continue to block SMTP from my address I might well consider implementing it.

Thank you again.