Here are the IP addresses you need to allow with your SPF (Sender Policy Framework) record:
Please add the domain ILLIAD.oclc.org to your SPF record, that way the ILLIAD.oclc.org SPF record will work even if the iP changes. If your SPF record does not allow ILLIAD.oclc.org, the current IPs to add are 206.107.42.249 and 206.107.42.254.
Here's how to set up DMARC with DKIM and SPF: Does ILLiad Support the DMARC Process using DKIM for Email Notifications?