Topic Last Modified: 2007-02-01
Use the Computer dialog box to specify the IP addresses or domain names to which you want to grant access or deny access. You can specify a single computer, a group of computers, or a domain name. The following options are available on the Computer dialog box.
- Single computer
-
Select this option to grant access or deny access to a single computer. If you select this setting, the following options are available:
- IP address Enter the IP address of a
single computer.
- DNS Lookup If you know the name of the
computer that you want to add to the list, but do not know the
IP address, click DNS Lookup. In the dialog box
that appears, enter the DNS name of the computer, and then click
OK. The DNS server will resolve the computer name to an
IP address and SMTP Server will automatically populate the
IP address field.
- IP address Enter the IP address of a
single computer.
- Group of computers
-
Select this option to grant access or deny access to all the computers within a specific subnet. If you select this option, you must enter the following information:
- Subnet address Enter the base
IP address for a group of computers.
- Subnet mask Enter the subnet mask that
specifies the range of IP addresses to which the base
IP address extends.
For example, if you enter a subnet address of 192.168.1.0 and a subnet mask of 255.255.255.0, all computers that have an IP address in the range of 192.168.1.1 to 192.168.1.254 are included in the group of computers.
- Subnet address Enter the base
IP address for a group of computers.
- Domain
-
Select this option to grant access or deny access to all the computers in a specific domain. If you select this option, you must enter the domain name in the Name field. Restricting access by domain name requires a reverse DNS lookup on each connection. The additional processing overhead can affect overall SMTP Server performance.