SMTP no-such-user issues

Steve Bertrand steve at
Wed Jun 18 12:18:25 UTC 2008

Steve Bertrand wrote:
> Hi everyone,
> We are experiencing an issue in regards to SMTP MTA relay responses 
> regarding 'no such user', and it *apparently* appears to be only 
> occurring when a particular site attempts to deliver email to us.

For the sake of completeness...

The problem has been found within the defining of a variable in chkuser:

"But I found the problem. chkuser_settings.h shows:
#define CHKUSER_NORCPT_STRING "511 sorry, no mailbox here by that name 
(#5.1.1 - chkuser)\r\n"

I changed the 511 to 550 (as shown here )"

I'm also told that version 2.09 of chkuser works around this problem.

For those who have recommended Postfix, I'd love to switch, however 
Qmail is tied so tightly into my mail infrastructure at this point that 
I don't think it would be possible without months and months of 
planning, and redeveloping a whole lot of internal management software.

Thanks everyone,


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