Justin Mason wrote:
>[snip]
>
> In fairness -- if you drop mail with no rDNS, you are dropping 3.6% of
> legit email in general, going by the test results for our RDNS_NONE
> rule... ;)
It just came to my mind that RDNS_NONE does not mean the client does not
have a reverse DNS, be it confirmed or just a PTR.
RDNS_NONE uses the rdns field determined from the Received headers, but
- some MTAs do not do rDNS lookup
- there may be a temp fail
- there may be a mismatch (PTR exists but doesn't resolve back to IP)
so the 3.6% include more than IPs without a (valid) PTR.
It would be interesting to get stats for each category, but this
requires doing the lookup in SA. which brings us back to an old request:
add the possibility to lookup rDNS in SA. Are there any caveats in
adding this? I am thinking of something like
resolve_ip (0|1|2)
where 1 means a PTR lookup only, and 2 a "double" lookup ("FcrDNS"), and
the lookup is only done on the most external relay?
