How do I change SMTP server hostname or IP address in AIX?

Make a backup and edit the Sendmail Configuration File (/etc/sendmail.cf) to point to the correct SMTP host.

cp /etc/sendmail.cf /etc/sendmail.`date +%Y%m%d.%H%M%S`
vi /etc/sendmail.cf

In VI search for the “DSsmtp” string and make the change according to your system configuration.

Sample By Hostname:

### Example SMTP Hostname:
DSsmtp:mailhost

Sample By IP Address:

### Example SMTP IP Address:
DSsmtp:[10.10.10.101]

Sample by DNS Name:

### Example Hosted SMTP Server:
DSsmtp:mail.bighostingcompany.com

Restart Sendmail

refresh –s sendmail

Test Email.

sendmail -v -t -femail@company.com email@company.com < /etc/motd