Re: disable spamhaus request

On 2025-04-18 at 09:40:29 UTC-0400 (Fri, 18 Apr 2025 09:40:29 -0400)
Bowie Bailey <[email protected]>
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
[email protected] or [email protected]
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
Not Currently Available For Hire