Which of the following access lists will allow only HTTP traffic into ...
The first thing to check in a question like this is the access-list number. Right away, you can see that the second option is wrong because it is using a standard IP access-list number. The second thing to check is the protocol. If you are filtering by upper-layer protocol, then you must be using either UDP or TCP; this eliminates the fourth option. The third and last answers have the wrong syntax.
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Which of the following access lists will allow only HTTP traffic into ...
Access Lists and HTTP Traffic
Introduction:
Access lists are used in network security to control the flow of traffic into and out of a network. They are typically implemented on routers or firewalls and can be used to filter traffic based on various criteria such as source/destination IP addresses, protocols, and ports. In this question, we are asked to identify the access list that will allow only HTTP traffic into network 196.15.7.0.
Solution:
To allow only HTTP traffic into network 196.15.7.0, we need to create an access list that permits TCP traffic on port 80 (which is the default port for HTTP). Let's analyze each option and determine the correct one.
Option A:
access-list 100 permit tcp any 196.15.7.0 0.0.0.255 eq www
This access list permits TCP traffic from any source IP address to the network 196.15.7.0 on port 80 (www). This is the correct option as it allows only HTTP traffic.
Option B:
access-list 10 deny tcp any 196.15.7.0 eq www
This access list denies TCP traffic from any source IP address to the network 196.15.7.0 on port 80 (www). This option would block all HTTP traffic instead of allowing it.
Option C:
access-list 100 permit 196.15.7.0 0.0.0.255 eq www
This access list permits traffic from the network 196.15.7.0 to any destination IP address on port 80 (www). This option does not restrict traffic to HTTP only and would allow any traffic originating from the network 196.15.7.0.
Option D:
access-list 110 permit ip any 196.15.7.0 0.0.0.255
This access list permits all IP traffic from any source IP address to the network 196.15.7.0. It does not specifically allow HTTP traffic only.
Option E:
access-list 110 permit www 196.15.7.0 0.0.0.255
This access list permits traffic with a source or destination port of 80 (www) from any source IP address to the network 196.15.7.0. While it allows HTTP traffic, it also permits traffic with port 80 as the destination, which may not necessarily be HTTP traffic.
Conclusion:
After analyzing each option, we can conclude that option A (access-list 100 permit tcp any 196.15.7.0 0.0.0.255 eq www) is the correct access list that allows only HTTP traffic into network 196.15.7.0.