I entered "Outbound SMTP Server" address in Central Admin. Now I need to tell my SMTP server to accept emails from my farm. How do I find which server/IP address in the farm trying to send emails?
SharePoint WFE are responsible to send the emails to user. I think you are talking about the relay setting. You should enter the WFE Ips their.
- IP addresses of Web Front End’s in you farm.
- But if you want to use all servers in the farm then select all except the list below option.