Sahil Tandon:
> On Sun, 2011-12-25 at 13:37:52 +1000, Nick Edwards wrote:
>
> In the absence of full information, here's a WAG:
>
> > ...
> > : NOQUEUE: reject: RCPT from unknown[41.203.141.1]: 450 4.7.1 Client host
> > rejected: cannot find your hostname,
>
> % host 41.203.141.1
> Host 1.141.203.41.in-addr.arpa not found: 2(SERVFAIL)
> ^^^^^^^^
> This is treated as a temporary error condition, so Postfix applies
> reject_tempfail_action, which defaults to defer_if_permit.
Confirmed. According to my copy of /usr/include/netdb.h:
#define TRY_AGAIN 2 /* Non-Authoritative Host not found, or SERVERFAIL */
Postfix uses the main.cf reject codes only in case of non-error.
Wietse