The option `exclude_domains` for dmarc reporting in `rspamd`[1] allows
to configure a list of domains and/or eSLDs (external effective second level
domain) to be excluded from dmarc reports.
Helpful because e.g. dmarc reports to hotmail.com always fail for me
with the following undeliverable notification:
The recipient's mailbox is full and can't accept messages now.
[1] https://www.rspamd.com/doc/modules/dmarc.html