The emails from Freshservice are sent through Sendgrid, which is our email service provider. If you are willing to use your own mail servers instead of Sendgrid to send and receive emails, you could use the custom mail server option available.

You could set this up by adding the IMAP and SMTP details of your mail server, to your freshservice Account, under Admin-->Support Channels-->Emails-->Edit(corresponding to your email address)-->Use your own mail server.