If you have a small number of clients who use the POP3 service,
you can create an exclusive group of computers that can access the
server. Computers that are permitted to use the service can be
identified by IP address, subnet mask, or domain name.
Warning
Identify a permitted computer by IP address only if you assign IP
addresses statically. If a Dynamic Host Configuration Protocol (DHCP)
server assigns temporary IP addresses to computers, you cannot
ensure a computer will always use the same IP address.
To grant access by IP address, subnet, and domain:
In the console tree, right-click a virtual server, and then
click Properties.
On the Access tab, click Connection.
Select Only the list below, and then click
Add.
Select one of the following options:
IP address. Type the static address of a single
computer. For example, 192.168.114.201.
Tip If you only know the name
of the computer, click DNS Lookup. Type the name of the
computer, and then click OK. If resolved, the IP address
appears in IP address automatically.
Group of Computers. Type the subnet address and mask;
for example, a subnet address of 172.17.131.0 and a subnet mask of
255.255.250.0
.
Domain. Type the complete domain name; for example,
nwtraders.microsoft.com
.
To add the computer, subnet, or domain to the list of permitted
computers, click OK.
Note By default, POP3 virtual
servers grant all computers access. If you create an exclusive
group of permitted users for one POP3 virtual server, the list
applies only to that one POP3 virtual server. To limit access to
other POP3 virtual servers, you must add groups of computers to
each instance of a POP3 virtual server.