On 17 June 2002, Adam Henry said:
> I am seeking others' verification of the way I interpret the following
> rejection in my rejectlog:
>
> ------------------------------------------------------------------------------
> 2002-06-17 08:50:47 17Jvy2-0002iB-00 rejected from idk.carlsoncraft.com (tcmail2.tcusa.com) [198.12.16.12]: temporarily unable to verify sender address <Service@???> (try later)
The "temporarily unable to verify sender address" is the clue here.
It's a DNS failure -- Exim is unable to resolve 'cceasy.com'.
Furthermore, it's a temporary problem, meaning that some DNS server
timed out, rather than returning a "no such domain" error. Exim rejects
with 4xx response in this case, meaning that the sender should try again
later.
cceasy.com resolves just fine for me, so either some DNS server has been
fixed since Exim logged this error on your server, or your DNS setup is
broken.
> I notice that while the helo is sent as "tcmail2.tcusa.com", the
> IP of the sending MTA is [198.12.16.12], which reverse-resolves to
> "idk.carlsoncraft.com". I have the following options set in
> exim.conf:
>
> sender_verify_hosts_callback = *
> sender_verify_callback_domains = *
> sender_verify_hosts = *
This is the one -- sender_verify_hosts just means that the domain of the
sender address must resolve. If Exim gets a hard "no such domain" DNS
failure, it rejects the message with a 5xx response; otherwise it
rejects with a 4xx response.
> What I am investigating into is which of these options prevents the
> above mail from being accepted. I also would like to know if anything
> else from the rejectlog looks out of the ordinary.
Nope, looks perfectly normal. sender_verify_hosts is a very useful
(though far from all-encompassing) tool for fighting spam. Use it and
be happy.
Greg
--
Greg Ward - software developer gward@???
MEMS Exchange http://www.mems-exchange.org
