In my current project, suddenly I started facing a problem where no email was coming to my organisation’s email address. So I need to check with my organisation’s network team, whether there is a problem. sends email from 52 IP addresses. So, I need to provide the all 52 IPs to my network team. The intention is to check whether any of the 52 IP addresses are blocked in my organisation.

I thought of sharing the information here so that if someone face similar issue, this is what you should do first.
Once you go to Salesforce, go to Setup -> Administer -> Email Administration -> Test Deliverability. You will find a screen like this-
If you click on the send button, 52 emails will be delivered to your email address. From there you can get all the 52 IP addresses and share with your network team.

Hope this will help to do initial analysis. Any feedback is always welcome.