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Emails bouncing with Reverse DNS Lookup failed

ladynewton
Member

Hello, 

I'm getting an error message when I try to email to an address in the US which had been getting through fine until recently. Coincindentally I went to the US recently and while I was there I couldn't send email from my O2 iPad (although I could receive email just fine). 

 

The error message I'm getting is:

 

Your message

 To:      Amy Gilthorpe
 Subject: Test email
 Sent:    Sun, 2 Sep 2012 12:00:52 +0100

did not reach the following recipient(s):

<Email address removed by Mod> on Sun, 2 Sep 2012 12:00:57 +0100
   The e-mail system was unable to deliver the message, but did not
report a specific reason.  Check the address and try again.  If it still
fails, contact your system administrator.
   < c2bthomr09.btconnect.com #5.0.0 SMTP; 572  MAIL REFUSED - Reverse
DNS failed; IP address mismatch in the HELO command.>
Reporting-MTA: dns; HEMV1AUKER.he.local

Final-Recipient: RFC822; <Email address removed by Mod>
Action: failed
Status: 5.0.0
X-Supplementary-Info: < c2bthomr09.btconnect.com #5.0.0 SMTP; 572  MAIL REFUSED - Reverse DNS failed; IP address mismatch in the HELO command.>
X-Display-Name: <Email address removed by Mod>

From: "P Newton" <Email address removed by Mod>
Subject: Test email
Date: 2 September 2012 12:00:52 GMT+01:00
To: "Amy Gilthorpe" <Email address removed by Mod>

 

My Outgoing mailserver is configured as SMTP.btconnect.com


Does anyone have any idea why the Reverse DNS lookup is failing? 

And why my iPad was unable to send mail while in the US?

 

Thanks in anticipation, 

Patricia

 

 

From Dave the Mod - Just a little anti-spam work.  Posting up your email address, even here, can lead to unwanted emails.  🙂

 

2 REPLIES 2

DaveA
BT Partner
BT Partner

Hi,

 

That's a strange one.  I've sent you a PM.

 

Dave

FSDSMAN
Power User

It is because you are sending on port 110 or default SMTP server settings. The internet provider that you connected to via WiFi in the states will reject any outgoing SMTP message on that port if the username and password is not authenticated by their RADIUS servers or what ever they use. They and most mail servers block this by default to stop an "open relay" You could however configure the device for web mail and send from there.