You may want to know what domain and SPF Address Ranges are needed for the schoolloop.com SPF record so you can stop spoofing spam by enabling SPF (Sender Policy Framework) on your spam filters.
schoolloop.com has published a public SPF record that clearly spells all the IP addresses authorized to send emails ending with schoolloop.com.
School Loop's SPF record is public and can be found from third-party Spoof Checker or SPF Record Checker. For example using Spoof Checker:
The valid IP addresses and domains for schoolloop.com are provided in the SPF record.
v=spf1 ip4:126.96.36.199/27 ip4:188.8.131.52 ip4:184.108.40.206 ip4:220.127.116.11/25 include:_spf.google.com include:support.zendesk.com include:spfa.mailendo.com include:mail.zendesk.com -all
Please note that once the SPF check is enabled on your anti-spam solution in your district, it will check the IP address for all incoming school loop emails to validate if they are indeed coming from authorized servers and it will block all spoofed emails.