The table in this post shows the firewall rules solution to meet the requirements in the “Firewall Rules” post. Additionally, the following list provides explanations for each of these requirements. For clarity, the rules are restated right before the explanation:
- Allow all HTTP traffic to a web server with an IP of 192.168.1.25.
Note that while HTTP traffic typically uses TCP, it can also use UDP. Because of this IP is used instead of TCP or UDP. - Allow all HTTP and HTTPS traffic to a web server with an IP of 192.168.1.25.
This requires two rules. One rule allows HTTP traffic by allowing port 80, and the second rule allows HTTPS traffic by allowing port 443. - Allow DNS queries from any source to a computer with an IP of 192.168.1.10.
DNS name resolution queries use UDP port 53. - Block DNS zone transfer traffic from any source to any destination.
DNS zone transfers use TCP port 53. - Block all DNS traffic from any source to any destination.
Using IP blocks both DNS name resolution queries on UDP port 53 and DNS zone transfers on TCP port 53. You could also implement this was two separate rules with one for UDP and one for TCP. - Implement implicit deny.
The implicit deny rule is always placed last and it blocks any type of traffic from any source to any destination using any port. Note that you could also have omitted rules 4 and 5 and placed the implicit deny rule after rule 3. It would still have met the requirements but wouldn’t have stressed the difference between TCP port 53 and UDP port 53.
Table: Firewall rules
Page 1 of 3 ACLs and Security+
Page 2 Firewall Rules and Security+
Page 3 Firewall Rules Solution (this page)
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Hi Darril,
In the diagram for ACL above, it says HTTP typically uses TCP but “can” use UDP. Now I know this is true but if it mainly uses TCP and so it says on your textbook in the list of protocols (table 3.1) that HTTP is known for TCP 80, would it be wrong to list the protocol as TCP over IP?
Thank you
>… would it be wrong to list the protocol as TCP over IP?
If you like…
Or in other terms, if there was a multiple choice question asking what protocol and port number does HTTP use, would TCP 80 or TCP/UDP 80 be “BEST” answer?
> (listen to me talking here…)
Huh?
> BUT, why not just eliminate the 1st part (that is redundant) of Rule 2
The goal with the answer is to ensure the reader understands how to create each rule to meet each requirement.
* If someone is looking for the rule to meet requirement 1, they can see it in the table.
* If someone is looking for the rules to meet requirement 2, they can see them in the table.
Notice that the first row is labeled Requirement 1 and the next two rows are labeled Requirement 2.
If the first part of Requirement 2 is omitted, it doesn’t provide a complete solution.
I took the test and failed yesterday due to running out of time after the performance based questions. None of them were as simplified as the examples you have here on your site. I have a strong networking background but the questions weren’t clear about what they were looking for. If they plan to include this type of questions they will need to expand the amount of time available. There were many different screens of data to be reviewed and then go back to provide the answer for each. They need to consider the time limit when developing the performance based questions.
Hi Karen,
Sorry to hear you dropped the test. It’s a tough test and CompTIA is frequently adding in new beta questions for testing, and adding them into the mix once they’ve tested them.
Two things to consider.
1) This page includes a list of blog posts related to performance-based questions you might find valuable: https://blogs.getcertifiedgetahead.com/security-blog-links/#Performance
This post gives valuable tips you can use as a strategy with performance-based questions. Tip 2 – Skip them. In other words, it’s best to do them last if they aren’t clear to you. This is especially useful if it’s a bogus beta question that hasn’t been tested.
2) This site (http://gcgapremium.com/pass-the-security-sy0-401-exam-the-first-time-you-take-it/) has a wealth of realistic performance-based practice test questions that aren’t possible in the app. As an example, Set 10 has 20 realistic practice test questions with drag and drop, matching, and fill-in-the-blank type questions.
Last, CompTIA would value your feedback on the lack of clarity with the questions, and the lack of time to do the questions.
I don’t know, but have begun to suspect that they are beta testing CASP questions within the Security+ exam. If you skip the questions, it’s no big deal. However, if you try to answer them, you have limited time to answer the real questions.
Hope this helps.
There is a performance based question that…. text deleted
Note: Please do not post questions on what you understand to be actual questions on the exam.
there is an ACL question on the exam…. text deleted
Note: Please do not post questions on what you understand to be actual questions on the exam.
took test 9/22/2015, didn’t pass. It was totally different from when I took it 8/6/2015. The performance base is what messing me up (network stuff is where I’m weak). I thought I figure it out enough to retake it. All the performance base questions was new , I just didn’t have a clue
Sorry to hear you didn’t pass. I am hearing from people that the questions are different, but still testing the same content. In other words, they tell me that because they understand the content, they are able to identify the correct answers.
CompTIA does stress the need for a good networking background. Because you recognize this as a week area, I’d suggest you build up your foundation of networking knowledge. You might want to consider pursuing the Network+ cert.
Good luck.
darril,
if you buy the apple app, can you use it on the ipad and iphone
Yes.
Doesn’t the first part of rule 2 include rule 1? So why list both rule 1 at all in the answer? They’re identical.
> Doesn’t the first part of rule 2 include rule 1?
Yes. However, the goal is to ensure the reader understands how to create the rule to meet each requirement.
If someone is looking for the rule to meet requirement 1, they can see it in the table.
If someone is looking for the rules to meet requirement 2, they can see them in the table.
> So why list both rule 1 at all in the answer? They’re identical.
For clarity.
Notice that the first row is labeled Requirement 1 and the next two rows are labeled Requirement 2.
If Requirement 1 was omitted, readers that didn’t get to Requirement 2 won’t have a solution.
(listen to me talking here…) BUT, why not just eliminate the 1st part (that is redundant) of Rule 2, and then allow port 443 going to IP 192.168.1.25?
So does the implicit deny rule mean that everything is blocked *except* for the 3 ALLOW items you entered above? The ALLOW entries will still work?
Yes. It’s explained more completely in the first post of this series: https://blogs.getcertifiedgetahead.com/acls-and-security/
You’re correct Deaven. Thanks for pointing that out. I just fixed it.
Requirement 2 states a destination IP of 192.168.1.25. However, the solution provided for Requirement 2 provides a destination IP of 192.168.1.10