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Outgoing email being blocked due to URL or keywords

Hooked
Posts: 9
Registered: ‎19-08-2014

Outgoing email being blocked due to URL or keywords

Hi,

I'm having a problem where my outgoing email is being blocked depending on content.

For instance including 'host' (as in TSO host) in the message body caused messages to fail to send a couple of weeks ago.

Today, after a lot of trial and error it seems that I'm unable to include this specific url address in an outgoing message:

    www.text-connect.co.uk

The bounce message is:

 

Hi. This is the qmail-send program at mediacopy.local.
I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

<david.xxx.xxx@googlemail.com>:
212.159.8.107 failed after I sent the message.
Remote host said: 552 D7ShkkImzrXCcD7SikxF9j message rejected due to spam or virus. If you believe this is in error please login to your portal or contact your ISP support team.
STARTTLS proto=TLSv1.2; cipher=ECDHE-RSA-AES256-GCM-SHA384; subject=/OU=Domain Control Validated/CN=relay.plus.net; issuer=/C=US/ST=Arizona/L=Scottsdale/O=GoDaddy.com, Inc./OU=http://certs.godaddy.com/repository//CN=Go Daddy Secure Certificate Authority - G2;

 

I've been unsuccessful in contacting customer services - can someone help ?   The URL is valid and part of my work.

Best wishes

 

 

David

4 REPLIES 4
Superuser
Superuser
Posts: 16,566
Thanks: 6,786
Fixes: 62
Registered: ‎22-08-2007

Re: Outgoing email being blocked due to URL or keywords

Hi David,

Can you be a bit clearer on what you are trying to do here please?  The diagnostics mention...

  • A google email address
  • Qmail-send program
  • relay.plus.net

If you are trying to send an email from a googlemail.com address via the Plusnet SMTP relay, then there might well be some unexpected issues.  Note that I can send an email containing that URL from one Plusnet address to another.

Can you please clairify...

  1. From which address are you sending?
  2. From what email program are you sending?
  3. Which SMTP server are you using?
  4. What address (domain) are you sending to?

Have you tried to reproduce this error within webmail?

Hooked
Posts: 9
Registered: ‎19-08-2014

Re: Outgoing email being blocked due to URL or keywords

Hi there,

Thanks for your reply and sorry for my slow reply.

I've just quickly send the tested this again, with the same message content and and all seems to be working OK.  I've a suspicion that the Plusnet Antispam system is a little aggressive on outgoing mail  based on key word content.

The recipient address was the redacted googlemail address.  My mail program is 'SME-Server with a roundcube client.

 

Following on, I'm interested in your question regarding

relay.plus.net

which is the Plusnet SMTP server we have been using for outgoing email for years.

Your reply suggests this is incorrect or perhaps legacy ?

Best

 

David

 

 

Superuser
Superuser
Posts: 16,566
Thanks: 6,786
Fixes: 62
Registered: ‎22-08-2007

Re: Outgoing email being blocked due to URL or keywords

Hi David,

Not legacy but potentially incorrect ... depending!!

 

In times gone by, irrespective of the domain of the FROM address, one tended to use the SMTP (relay) server on the network one was connected to without the need to authenticate with the server on port 25.  When the vast majority of users were only ever connected to the same network access point, that was not too much of an issue.  Then we became mobile and found that we needed to change the SMTP server every time we changed networks!!!

To address that we moved to requiring authenticated connections and were still able to send from any address.

Then people sought to abuse email, so many network providers blocked general access to port 25 on external servers and email submission (as opposed to relay) moved to the correct port 587.

That still left the issue that people can fake being someone@anywhere.com and send such emails via smtp.somewhereelse.com - such has been mitigated by the implementation of SPF

SPF effectively states that emails from @anywhere.com should only be sent via smtp.anywhere.com so that if the RECEIVER sees such emails coming from @somewhereelse.com THEY can consider it to be SPAM it THEY chose to do so.

 

Hence my questions - if was not clear what address you were trying to send from via which SMTP server to what address.  In the SPF world, the question of "Has this FROM come via the correct SMTP sever to this RECEIVER?" is dealt with in the receiver's domain.

HTH and makes sense?

Hooked
Posts: 9
Registered: ‎19-08-2014

Re: Outgoing email being blocked due to URL or keywords

Hi Townman,

 

Thanks for the explanation.  I'm fairly familiar with the  systems and your SPF explanation gave some handy back ground. 

I'm pretty sure when I checked with a diagnostic tool ( www.mail-tester.com ), our SPF settings checked out OK for sending from plus net.

Going back to the original question, the issue didn't seem to be 'from' address related - it was 'body' content seemingly causing the bounce.

 

Anyway, fingers crossed it's all working now.

 

Thanks for your help.

 

Best

 

 

David