MTCNA Exam Dumps : MikroTikCertified Network Associate Exam

DNS primarily uses UDP port 53 for most query/response operations. However, TCP port 53 is also used, particularly for larger responses (such as DNS zone transfers or DNSSEC).

A.✔UDP – Used for standard DNS queries due to lower overhead.

B.✔TCP port 53 – Used when UDP is insufficient, especially for zone transfers (AXFR/IXFR).

Extract from MTCNA Course Material – DNS and Networking Services:

“DNS typically uses UDP/53, but falls back to TCP/53 for larger queries or zone transfers.”

Extract from MikroTik Wiki – DNS Settings:

“DNS uses UDP for general queries. TCP is used when UDP cannot accommodate the size of the response.”

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The action=redirect is used only in the dstnat chain to redirect traffic to a local port (e.g., for transparent proxy or DNS capture). It is not valid in the srcnat chain.

A.✘Incorrect – RouterOS will not permit redirect in srcnat.

B.✔Correct – redirect is only supported in dstnat.

Extract from Official MTCNA Course Material – NAT Actions:

“Redirect is used in the dstnat chain to force traffic to a specific port on the local router.”

Extract from MikroTik Wiki – NAT Action Reference:

“Action=redirect is only meaningful in dstnat and is used to redirect traffic to router-local services.”

Extract from René Meneses Study Guide – NAT Table:

“Redirect cannot be used in srcnat. Only valid in dstnat for local service interception.”

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Bridging loops occur when there are multiple active paths between switches or bridge interfaces, causing broadcast storms or MAC table instability. MikroTik RouterOS supports both STP (Spanning Tree Protocol) and RSTP (Rapid Spanning Tree Protocol) to detect and block redundant paths.

A.✔RSTP – Faster and preferred protocol to prevent loops.

B.✔STP – The original protocol, slower convergence but still effective.

C.✘Connection tracking – Not related to Layer 2 loop prevention.

D.✘UDP filter – Filters specific traffic types, doesn’t handle loops.

E.✘ICMP filter – Not relevant to Layer 2 loop protection.

Extract from Official MTCNA Course Material – Bridging and STP:

“STP or RSTP must be enabled to prevent bridging loops. RSTP is the recommended version due to faster convergence.”

Extract from René Meneses MTCNA Study Guide – Bridging:

“Always enable STP or RSTP when using bridges with multiple paths to prevent Layer 2 loops.”

Extract from MikroTik Wiki – STP / RSTP:

“STP and RSTP are loop prevention mechanisms for bridges. They dynamically block redundant links.”

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