JN0-351 Exam Dumps - Juniper JNCIS-ENT Questions and Answers

 A firewall filter is a Junos security solution to filter or control traffic at the data plane as they enter or exit an interface 1 .  A firewall filter consists of one or more terms, each with a set of conditions and actions 2 .  The device evaluates every packet against the firewall filter terms in the order they are defined, and performs the actions specified in the first term that matches the packet 3 .  If no term matches the packet, the device discards the packet by default 3 .

In the exhibit, the firewall filter  mac-address  is applied to the  family ethernet-switching  and involves filtering MAC addresses. There are two terms,  term one  and  term two , each with different conditions and actions. The  from  statement specifies the match conditions, and the  then  statement specifies the actions.  If the  from  statement is omitted, all packets are considered to match and the actions in the  then  statement are taken 2 .  If the  then  statement is omitted, the packets that match the conditions in the  from  statement are accepted by default 2 .

Term one  logs traffic from a specific source MAC address  88:05:00:29:3c:de/48 .  The  log  action is a nonterminating action, which means that the device continues to evaluate the packet against the remaining terms in the filter 2 . Therefore, traffic that matches the  from  statement in term one is not discarded, and option A is incorrect.

Term two  accepts all other traffic not specified in term one.  The  then accept  action is a terminating action, which means that the device stops evaluating the packet against the filter and forwards the packet 2 . Therefore, all traffic not matching the  from  statement in term one is accepted by term two, and option D is correct.

Term two  does not have a  from  statement, which means that all packets are considered to match this term. Therefore, traffic matching the  from  statement in term two is not logged, and option B is incorrect.

Term one  does not have a  then  statement other than the  log  action, which means that the packets that match the  from  statement are accepted by default. Therefore, traffic that matches the  from  statement in term one is accepted, and option C is correct.

The exhibit shows the configuration of RSTP on EX-4, which has the command  force-version stp .  This command forces the switch to use the legacy STP protocol instead of RSTP, even though the switch supports RSTP 1 .  This means that EX-4 will not be able to take advantage of the faster convergence and enhanced features of RSTP, such as edge ports, link type, and proposal/agreement sequence 2 .

The other switches in the network are likely to be running RSTP, as it is the default protocol for EX Series switches 3 . Therefore, there will be a compatibility issue between EX-4 and the other switches, which will result in longer convergence times and suboptimal performance.  The switch will also generate a warning message that says “Warning: STP version mismatch with neighbor” when it receives a BPDU from a RSTP neighbor 1 .

To solve this problem, the force-version command must be removed from EX-4, so that it can run RSTP natively and interoperate with the other switches in the network. This will enable faster convergence and better stability for the network topology.  To remove the command, you can use the  delete protocols rstp force-version  command in configuration mode 1 .