Email Source: Gandi

Homepage: https://www.gandi.net/

This source is known to forward email

Capable of generating DMARC compliant email for others

Yes

Gandi supports DMARC compliance via SPF and DKIM.

Capable of signing email with DKIM for others

Yes

Gandi does support DKIM signing for customer domains. See https://docs.gandi.net/en/gandimail/faq/general_questions.html#does-gandimail-support-dkim

Capable of sending SPF compliant email for others

Yes

For SPF configuration guidance, contact Gandi support or visit: https://docs.gandi.net/en/domain_names/faq/record_types/spf_record.html