In order for JIRA to communicate through e-mails, you need to configure or register your mail servers in JIRA. There are two types of mail servers you need to configure:
JIRA will only let you to set up one SMTP mail server which will be used as the primary mail server to send out e-mails. You can configure any number of POP/IMAP mail servers. This allows JIRA to pick up e-mails from multiple sources.
Mail server configuration details are maintained by the JIRA administrator.