On 2025-04-18 at 09:40:29 UTC-0400 (Fri, 18 Apr 2025 09:40:29 -0400) Bowie Bailey <bowie_bai...@buc.com> is rumored to have said:
[...] > With that being said, he was not incorrect in this instance. > > The response received from Spamhaus indicates that you were blocked due to > using a public DNS server. > > describe RCVD_IN_ZEN_BLOCKED_OPENDNS ADMINISTRATOR NOTICE: The query to > zen.spamhaus.org was blocked due to usage of an open resolver. See > https://www.spamhaus.org/returnc/pub/ > > You should double-check your nameserver setup and make sure it is doing what > you think it is doing. Also double-check that the system running SA is > actually configured to use your local nameserver (in /etc/resolv.conf or > similar) and check for a dns_server setting in the SA config files that might > be pointing somewhere else. It may be useful to note that in principle, Spamhaus blocks *open* resolvers, not just the behemoth resolver farms operated by Google, CloudFlare and others. Some years ago such resolvers were problematic due to amplification attacks, to the point where people operated nag-bots scolding operators for their open resolvers. It is possible for anyone operating a resolver to accidentally leave it open. I do not KNOW whether Spamhaus actively looks for open resolvers to block. I would if I were in their place, but I'm not. -- Bill Cole b...@scconsult.com or billc...@apache.org (AKA @grumpybozo and many *@billmail.scconsult.com addresses) Not Currently Available For Hire
