Am 16.05.2016 um 02:26 schrieb Bill Cole:
On 15 May 2016, at 9:51, Dianne Skoll wrote:On Sun, 15 May 2016 13:25:34 +0200 Matus UHLAR - fantomas <uh...@fantomas.sk> wrote:Note that the TTL is 3600 for both reverse and forward records. There are blacklists that won'd delist your IP if your TTL is this short, e.g. sorbs requirs at least 14400.According to http://www.sorbs.net/delisting/dul.shtml: Also, the Times to Live of the PTR records need to be 43200 seconds or more. This is an arbitrary limit chosen by SORBS.What, really? What's the rationale for that requirement? That a short TTL is "too dynamic"? That seems a little aggressive, IMO.It's also VERY unevenly enforced. Amazon SES and Office365/Outlook.com outbounds emit substantial spam, have names that embed their last 1 or 2 octets, and PTR TTL's of 900 and 3600 respectively. The MS sewer outlets HELO with names that resolve to IPs other than those they actually use, and the PTR on the IPs used typically resolve to a names with a zero TTL. SORBS will list these as spam sources but not as dynamic, so there's clearly some subjective judgment in use
easy to understand - the "dul.dnsbl.sorbs.net" is much heigher weighted in most setups - here it has a postscreen-reject-score and a host there needds to be on a least one common DNSWL to have any chance
well, and they are not dynamic machines - the distinction is not only dynamic - the point is ENDUSER-MACHINE which has not point to connect to a public MX at all (independent of how often the word static appear in the PTR, a office-machine is not a mailserver and has no business on port 25) versus a server
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