Which two statements are correct about firewall filters in the Junos OS? (Choose two.)
A.
Firewall filters are stateless.
B.
Firewall filters are used to control routing information that is exchanged between devices.
C.
Firewall filters are used to control traffic passing through the device.
D.
Firewall filters can only be applied to traffic entering the device.
http://www.juniper.net/documentation/en_US/junos13.2/topics/concept/firewall-filter-overview.html
A stateless firewall filter, also known as an access control list (ACL), does not statefully inspect traffic. Instead, it evaluates packet contents statically and does not keep track of the state of network connections.
To influence which packets are allowed to transit the system and to apply special actions to packets as necessary, you can configure stateless firewall filters. A stateless firewall specifies a sequence of one or more packet-filtering rules, called filter terms. A filter term specifies match conditions to use to determine a match and actions to take on a matched packet. A stateless firewall filter enables you to manipulate any packet of a particular protocol family, including fragmented packets, based on evaluation of Layer 3 and Layer 4 header fields. You typically apply a stateless firewall filter to one or more interfaces that have been configured with protocol family features. You can apply a stateless firewall filter to an ingress interface, an egress interface, or both.