>>>>> "ptld" == postfix <post...@ptld.com> writes:
>> How can I reject connections from generic Forward Confirmed Reverse DNS >> (FCrDNS) like “123-45-67-8.your.isp.com”. ptld> I do not know if there is an easier way but you could make a script using ptld> check_policy_service or a milter to check if client name contains client ptld> IP. However i wonder how complicated the filter rules would be ptld> considering IPv6 and the different ways an address could be abbreviated. ptld> I have also seen some providers reverse the IPv4 in the FQDN. Also some ptld> legit mailers include the last part of the servers IP in the FQDN for ptld> large companies with many servers like gmail/google. I am interested only in IPv4. I know with Spamhaus some ISPs, Cloud Service Providers are blocked with policy block lists. Funny I discovered this when I wanted to register to barracudacentral.org rbl. It was blocked by Spamhaus. Now they have cleared their AWS ip from Spamhaus and this time their DMARC policy is rejected them.
