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RE: SMTP Invalid Address (501 5.5.4)

From: Steve Holme <>
Date: Tue, 20 May 2014 22:03:41 +0100

On Tue, 20 May 2014, Tom Sparrow wrote:

> I am extremely sorry for delay in responding.

Don't worry about it - I'd like to think we're a pretty chilled out bunch
here and don't stress about that sort of stuff!!

Anyway you saw how long it took me to respond and I'm one of the more
frequent posters <BG> Sorry about that ;-)

> A dummy valid hostname could be a string that follows hostname
> specification as per RFC 952 and RFC 1123.

Whilst I'm pretty familiar with most of the email related RFCs I'm not
familiar with either of those, unfortunately, and as I got a little lost in
RFC 952 so I only really read the SMTP section of RFC 1123.

> Please check the patch that possibly solves "501 5.5.4 Invalid Address"
> issue when machine's hostname is set to some invalid value.

Whilst I understand the patch, and my apologies if I am being a little slow
here, I'm not entirely sure I fully understand the problem still. I think I
have a few ideas as to what could be happening but would you be able to post
a log of the communication between either your app or the curl command line
tool and the problematic server (with verbose output turned on
CURLOPT_VERBOSE with libcurl or -v with curl) to see what is being sent back
and forth and why the 501 is being returned - It will also make sure I am on
the same page as you so to speak?

Many thanks

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Received on 2014-05-20