We use MailChimp to send comms to our business and Sophos Email Gateway blocks messages from it with reasoning "Bulk".
Mailchimp uses our Domain name as an envelop, so we whitelist the address "email@example.com" to allow messages to be delivered.
However if I understand it correctly adding sender in inbound allow list means it will skip all security checks (including SPF/DKIM/DMARC) which means this particular address "firstname.lastname@example.org" can easily be spoofed now?
If that's right then is there a way to customize what checks to skip (Bulk in this case) and what to leave in place?
After contacting Sophos support the only option for this seems to be is to Enforce Sender Authentication in "Inbound Allow/Block" settings.
It means the inbound filters will be bypassed only if…
I think the best work-around for this would be to create a separate policy for the specific email and remove checks on 'Bulk' emails. Then add your generic spoofing protection features (i.e. SPF/DKIM/DMARC). Not ideal but I'm sure it would work as a quick fix? Let me know how it goes as I can see this being an issue for myself in future.
I can't seem to be able to apply Policies to a specific external email address, policies can be applied to our organization's Users, Groups or Domains only?
It means the inbound filters will be bypassed only if the messages from this sender pass at least one form of DNS authentication (DMARC,SPF or DKIM).