On Thu, 27 Nov 2003, Chris Edwards wrote:
> Some composite DNSBLs e.g. sorbs (www.sorbs.net) return multiple A records
> where an IP is guilty of multiple offences. This is different from
> the bitmask response used by RBL+, blitzed and others.
>
> Can anyone help me clarify exim's behaviour in the multi-A case ?
From the ChangeLog for 4.21:
35. If a DNS black list lookup returned more than one A record, Exim ignored
all but the first. It now scans all returned addresses if a particular IP
value is being sought. In this situation, the contents of the
$dnslist_value variable are a list of all the addresses, separated by a
comma and a space.
> I assume that:
>
> dnslists = bl.example.org=xxx
>
> is true if any of the A records returned equals xxx.
Yup.
> But what about:
>
> dnslists = bl.example.org!=xxx
>
> Is this true only if *no* A record equals xxx ??
Yes; != is precisely the negation of = in this context. Exactly the same
code is obeyed in each case - then the answer is negated for !=.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book: http://www.uit.co.uk/exim-book
