I came across this message while searching the archive to answer the
question as to why callout sender verification was occasionally failing
with an apparently illegal response to the RSET command.
> Are you doing postmaster and/or random address callout?
> If so, the problem is that after doing one RCPT TO, my original code
> issued a RSET because some sites refuse more than one RCPT TO for null
> envelopes.
> Unfortunately, some sites do not implement RSET correctly, hence the
> failure you see.
I am using sender/callout=defer_ok,random,15s
I have received two complaints in the last couple of days from senders who
can't understand why they can't send to us. In both cases the dialogue
suggested that when testing the random address the 550 Unknown local part
response was received in response to an RSET examples appended). In both
cases, when I performed the dialogue manually the response to the RCPT TO:
was delayed, and in one case by roughly 15 seconds (and the server at the
other end was running Exim 4.20 so I am sure it was behaving correctly!)
In the other case the delay was more variable. In both cases the response
to the RSET was correct.
My guess is that the remote end was applying a delay to the response to a
bad recipient and the timer at both ends expired simultaneously so that
the RSET was sent from my end just as the delayed 550 response was being
sent from the remote end. I have now increased the timeout to 30s but the
same thing could still happen occasionally. If this is what is
happenning, perhaps the code should specifically allow for an apparent
invalid response to the RSET which is the expected 550 response to the
preceding RCPT TO.
Apologies if I have got the wrong end of the stick.
Richard
--
Richard Gilbert
Corporate Information and Computing Services
University of Sheffield, Sheffield, S10 2TN, UK
Phone: +44 114 222 3028 Fax: +44 114 222 3040
> > host woodchuck.shef.ac.uk [143.167.2.43]: 550-Verification failed for <leonies@???>
> > 550-Called: 137.82.27.15
> > 550-Sent: RSET
> > 550-Response: 550 unable to verify recipient: woodchuck.shef.ac.uk-1057171628-testing@???
> > 550 unrouteable sender address
and
> > 550-Verification failed for <ukcrypto-admin@???>
> > 550-Called: 193.201.200.170
> > 550-Sent: RSET
> > 550-Response: 550 Unknown local part marmot.shef.ac.uk-1057567489-testing
> > 550 unrouteable sender address
