Reverse Engineering from ACL to Address Range

Some exam questions might not ask that you pick the ACL statement that needs to be configured, instead asking that you interpret some existing access-list commands. To answer these types of questions, you need to determine the range of IP addresses matched by a particular address/wildcard mask combination in each ACL statement.

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Under certain assumptions that are reasonable for CCENT and CCNA, calculating the range of addresses matched by an ACL can be relatively simple. The low end of the range is the address field, and you find the high end of the range by adding the address to the WC mask. That’s ...

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