[Rspamd-Users] Peer has wrong DMARC policy. How to override in order to ACCEPT mail ?

[Andrew Lewis]

Hi Håkon,

On Wed, 2025-10-15 at 16:10 +0200, Håkon Alstadheim via Users wrote:
> My ISP is on occasion sending me system emails (NDNs) from their 
> internal hosts that are not covered by ther spf and DKIM records. I 
> *want* those status messages. The sending host is below a "protected"
> (for want of a better word) domain: altibox.no.  What is the cleanest
> way to do this? Mail headers in the NDN are:

Increasing scoring for DMARC failures mightn't be a generally good idea
(forcing rejection is a worse still idea). You might rather use
`whitelist` module to increase penalties for failed DMARC checks where
it's safe to do.

Alternatively, we might disable DMARC for domains where it causes
trouble. We can do that by adding a `condition`. `settings` module is
another way to do it but I think it's less favourable for a scenario
such as this one. Another approach is to use `composites` and user-
defined rules, probably in the form of `multimap`.

```
-- /etc/rspamd/lua.local.d/conditions.lua

rspamd_config:add_condition('DMARC_CHECK', function(task)
  local hfrom = task:get_from('mime')
  if not (hfrom and hfrom[1]) then return true end
  if hfrom[1].domain == 'altibox.no' then return false end
  return true
end)
```

https://docs.rspamd.com/configuration/settings/
https://docs.rspamd.com/configuration/composites/
https://docs.rspamd.com/modules/multimap/

Best,
-AL.