Re: [exim] Detect missing reverse dns

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Author: Todd Lyons
Date:  
To: Exim Mailing List
Subject: Re: [exim] Detect missing reverse dns
On Sat, Jul 18, 2009 at 7:39 AM, Dean Brooks<dean@???> wrote:
>>           !hosts         = ${lookup dnsdb{ptr=$sender_host_address}{$value}fail}
> Try this instead:
>          !condition     = ${lookup dnsdb{defer_never,ptr=$sender_host_address}{yes}}


Ugh, when I have tunnel vision it is annoying. It's a condition, not
a host. Duh.

> The "defer_never" is important.  Without it, you might end up sending
> a temporary error (4xx) code back to the sender if any part of the DNS
> lookups hang for some reason.  Unless that's what you want to have happen.
> There's more detail about the defer_xx items in section 9.12 in spec.txt.


My gut reaction was that a 4xx is what I want, but I will err on the
side of caution first.

> We also don't want to use "fail" in the failure of the lookup unless
> you want to cause a 4xx code back to the sender if they don't have a
> PTR record.  That would be bad.


Makes sense, that verbage about fail didn't quite make a distinction
to me about when to use it the first few times I read it, I'll read it
again and see if I can understand the context to use it.

Thank you.

-- 
Regards...      Todd