Security rules are essentially firewall rules, which you can use to permit traffic between Compute Classic instances in different security lists, as well as between instances and external hosts.

The source and destination specified in a security rule can be either a security IP list (that is, a list of external hosts) or a security list.

When you create an instance by using the web console, if you accept the default settings and don’t specify any security lists that you want to add your instance to, then your instance is added to a default security list. Any security rules that specify this default security list as a source or destination automatically apply to the instance when the instance is created.

You can create security lists and add instances to those security lists either while creating an instance, or later on when the instance is running. You can then define appropriate security rules that control traffic to and from all instances in the specified security lists.

A security rule is a firewall rule that you can define to control network access to Compute Classic instances over a specified security application.

1. Sign in to the Compute Classic console. If your domain spans multiple sites, select the appropriate site. To change the site, click the Site menu near the top of the page.
2. Click the Network tab.
3. Click Create Rule.
   The Create Security Rule dialog box is displayed.
4. Enter or select the following:
   • Enter a name for the new security rule.
   • By default, new security rules are enabled. If you’d like to enable the rule later, then set Status to Disabled.
   • In the Security Application field, select the security application that you want to enable traffic over.
   • In the Source field, select the security list or security IP list from which traffic over the specified protocol should be allowed.
   • In the Destination field, select the security list or security IP list to which traffic should be allowed.
   • Enter a meaningful description for the rule.
5. Click Create.

You can update a security rule to enable or disable it.

1. Sign in to the Compute Classic console. If your domain spans multiple sites, select the appropriate site. To change the site, click the Site menu near the top of the page.
2. Click the Network tab.
3. Identify the security rule that you want to update. From the menu, select Update.
4. In the Update Security Rule dialog box, change the Status as required, and click Update.

If a security rule is no longer required, you can delete it.

1. Sign in to the Compute Classic console. If your domain spans multiple sites, select the appropriate site. To change the site, click the Site menu near the top of the page.
2. Click the Network tab.
3. Go to the security rule that you want to delete. From the menu, select Delete.