SpamTitan allow SPF verification. It can be enabled in:
System Setup > Mail Relay > Sender Controls.

When enabled there is an exemption list where you can IP addresses of mail servers which you want to be exempt from the SPF test.

For more information please click the button below.

You can enable DKIM in SpamTitan through:
System Setup > Mail Relay > DKIM.

For more information please click the button below.

Create a free OnDMARC account to test your configuration.