To configure an SMTP server to only accept connections from certain IP addresses, follow these steps:
1. Open the SMTP configuration file. The name of the file and its location depend on the SMTP server you are using.
1. Find the security settings area. You can use the keywords “security”, “access control”, or “connection control” to find this area.
1. Set allowed IP addresses. Use syntax similar to the following: (example: 10.0.0.0/24 to allow all traffic from the 10.0.0.x network):
allow\_ips=10.0.0.1, 10.0.0.2, 10.0.0.0/24
1. Save changes and restart the SMTP server.
With these steps, only the IP addresses you specified will be able to connect to the SMTP server. All other IP addresses will be rejected. This will help improve the security of your SMTP server by limiting the risk of attacks and unauthorized intrusions.
