A VLAN with a gateway offers no security without the addition of:

A.
An ACL.

B.
802.1w.

C.
A RADIUS server.

D.
802.1d.

Explanation:
A gateway in a VLAN connects to another network. The other network can be the Internet, another subnet on
the network or another VLAN. The gateway will be a router and for security, it should also be a firewall.
A firewall is a system designed to prevent unauthorized access to or from a private network. Firewalls are
frequently used to prevent unauthorized Internet users from accessing private networks connected to the
Internet, especially intranets. Firewalls use ACLs (access control lists) to determine which traffic is allowed
through the firewall. All traffic entering or leaving the intranet passes through the firewall, which examines each
message and blocks or allows the message depending on rules specified in the ACL. The rules in the ACL
specify which combinations of source IP address, destination address in IP port numbers are allowed.