Signature 365 SMTP host list and IP whitelist
Find regional SMTP hosts and IP addresses to whitelist for Signature 365 server-side mail flow.
Microsoft 365 integration
When Microsoft 365 server-side signatures are configured, email is routed from Microsoft 365 to Signature 365 for signature injection, and back again to Microsoft 365 for delivery. Email is routed via Signature 365 using the Simple Mail Transfer Protocol (SMTP). You can find the host for the region where your Signature 365 account is hosted in the table below:
| Region | Region code | Host |
|---|---|---|
| Australia | au | smtp.au.signature365.net |
| Canada | ca | smtp.ca.signature365.net |
| European Union | eu | smtp.eu.signature365.net |
| United Arab Emirates | ae | smtp.ae.signature365.net |
| United Kingdom | uk | smtp.uk.signature365.net |
| United States | us | smtp.us.signature365.net |
If you add additional include statements to the Sender Policy Framework (SPF) record for your domain, your SPF record may exceed the 10 Domain Name System (DNS) lookup limit. In that case, you can add the IP addresses directly instead. You can find the IP addresses for the region where your Signature 365 account is hosted in the table below:
| Region | Region code | SPF record | IP addresses |
|---|---|---|---|
| Australia | au | spf.au.signature365.net | 20.53.65.59 |
| Canada | ca | spf.ca.signature365.net | 20.48.141.200 |
| European Union | eu | spf.eu.signature365.net | 20.54.238.131 |
| United Arab Emirates | ae | spf.ae.signature365.net | 20.74.238.135 |
| United Kingdom | uk | spf.uk.signature365.net | 20.49.163.140 |
| United States | us | spf.us.signature365.net | 52.148.165.43 |