MikroTik MTCRE Practice Exam

• A. ICMP Correct answer
• B. UDP
• C. MNDP
• D. ARP Correct answer

The 'check gateway' function in MikroTik routes uses ICMP or ARP to verify that the specified gateway is reachable. ICMP works by sending echo requests (pings) to the gateway, while ARP checks for a valid ARP response at Layer 2. These are the only two protocols supported for this purpose; they directly test gateway availability at the network and data link layers.

• A. 30
• B. 10
• C. 1 Correct answer
• D. 255

The 'target-scope' value in a static route determines how far the router will look for a valid gateway when resolving recursive routes. By default, RouterOS sets 'target-scope' to 1 for static routes, meaning it will only consider directly reachable next hops without further recursion. This ensures that static routes resolve quickly and do not depend on other routes with higher scopes.

• A. True
• B. False Correct answer

When configuring a static route on MikroTik routers, you only need to specify the gateway. The router will automatically determine the correct outgoing interface based on the gateway's IP address and the existing routing table. Manually specifying the interface is only necessary in rare cases, such as when using point-to-point links or when the gateway is not directly reachable.

• A. None, because distance is >=10
• B. Both
• C. 10.10.10.10
• D. 10.20.20.20 Correct answer

Routers select the route with the most specific (longest prefix match) destination, not the lowest administrative distance, when forwarding packets. The /30 route (10.1.1.4/30) is more specific than the /24 route (10.1.1.0/24), even though its distance is higher. The IP address 10.1.1.6 falls within the 10.1.1.4/30 subnet, so the router will forward the packet to the gateway 10.20.20.20.

• A. True
• B. False Correct answer

BGP (Border Gateway Protocol) uses TCP as its transport protocol, specifically TCP port 179. This means BGP peers only need IP connectivity, not direct Layer 2 adjacency. eBGP peers are often one hop away, but with multihop eBGP (using the 'ebgp-multihop' setting), BGP sessions can be established over multiple hops, even if the routers are not directly connected at Layer 2.

• A. IP address
• B. MAC Address Correct answer
• C. VLAN ID
• D. 802.11g

When an IP host sends an ARP request, it is asking 'Who has this IP address? Tell me your MAC address.' The purpose of ARP (Address Resolution Protocol) is to map an IP address to a MAC address so the host can send frames on the local network. The response to an ARP request always includes the MAC address associated with the requested IP address.

• A. /31 subnet Correct answer
• B. /24 private subnet
• C. /32 address on each side of the link
• D. /30 subnet

A /31 subnet is typically used for point-to-point links because it provides exactly two usable IP addresses, which matches the requirement for each end of the link. This avoids wasting IP addresses, as only two hosts need to communicate directly. Using /31 is efficient and is supported by modern networking equipment for point-to-point connections.

• A. Address=10.0.0.1/32 network=10.0.0.254 Correct answer
• B. Address=10.0.0.1/24 network=10.0.0.0
• C. Address=1.1.1.1/32 network=10.0.0.0 Correct answer
• D. Address=10.0.0.1/32 network=10.0.0.0 Correct answer

On point-to-point links, /32 addresses are commonly used because there are only two endpoints and no need for a broadcast or network address. Assigning a /32 address to each end ensures that only the specific host is addressed, which is ideal for tunnels or PPP links. The 'network' field in MikroTik is used for routing advertisements and does not affect the point-to-point addressing itself.

• A. 802.11g
• B. IP address
• C. MAC Address Correct answer
• D. VLAN ID

The correct answer is C: MAC Address. When a device sends an ARP (Address Resolution Protocol) request, it is specifically looking to resolve an IP address to a MAC address, which is necessary for communication on a local network. Option A (802.11g) refers to a wireless networking standard, not an address type. Option B (IP address) is what the device already has and is trying to resolve, not what it is hoping to receive. Option D (VLAN ID) is related to network segmentation and not relevant to ARP requests.

• A. True Correct answer
• B. False

RouterOS natively supports /31 addressing on point-to-point Ethernet links as defined in RFC 3021. No special interface configuration is needed — simply assigning a /31 address under /ip address creates a valid two-host connected route on the interface.

• A. True Correct answer
• B. False

PPPoE (Point-to-Point Protocol over Ethernet) uses Ethernet frames and relies on broadcast packets for discovery (PPPoE Active Discovery Initiation, or PADI). These broadcast packets do not traverse routers, as routers separate broadcast domains. Therefore, a PPPoE server and its clients must be in the same broadcast domain, with no routers in between, for the discovery process to work.

• A. (PPPoE over PPTP) over EOIP Correct answer
• B. (PPPoE over EoIP) over PPTP
• C. (PPTP over PPPOE) over EOIP Correct answer
• D. (PPTP over EOIP) over PPPOE Correct answer

The correct setups are those where tunneling protocols are layered in a way that each protocol can function as a transport for the next. PPPoE can be run over PPTP, and the resulting tunnel can be carried over EOIP, since EOIP can transport Ethernet frames. Similarly, PPTP can be run over PPPoE, and that tunnel can be carried over EOIP. PPTP over EOIP over PPPoE is also valid because EOIP can be carried over PPPoE, and then PPTP can be established over that. The incorrect option tries to run EOIP over PPTP, which is not supported because PPTP does not transport Ethernet frames directly, which EOIP requires.

• A. True Correct answer
• B. False

In MikroTik RouterOS, you can bridge different interface types, including VLAN and PPTP interfaces. The bridge interface acts as a virtual switch, allowing traffic to pass between its member interfaces regardless of their underlying technology. This is often used to extend Layer 2 connectivity over VPN tunnels or to integrate remote users into a local VLAN.

• A. True
• B. False Correct answer

Router A cannot use the /ppp secret accounts from Router B to authenticate PPPoE customers because each router maintains its own local user database. PPPoE authentication is handled locally on the router acting as the PPPoE server. Unless you configure a shared external authentication source like RADIUS, the secrets are not shared between routers, so Router A has no access to Router B's /ppp secret entries.

• A. True Correct answer
• B. False

EoIP (Ethernet over IP) operates at Layer 2, encapsulating complete Ethernet frames including any 802.1Q VLAN tags. This allows VLAN-tagged traffic to pass through the tunnel unchanged, transparently extending Layer 2 connectivity between two IP-routed sites.

• A. 1.2.3.4 Correct answer
• B. 0.0.0.0.
• C. 0.0.0.1 Correct answer

OSPF area IDs can be written either as a 32-bit dotted decimal number (like 1.2.3.4 or 0.0.0.1) or as a simple decimal integer. Both 1.2.3.4 and 0.0.0.1 are valid area IDs for a new OSPF area. The area ID 0.0.0.0 is reserved for the backbone area and should not be used for other areas.

• A. Neighbors Correct answer
• B. Neighbors ID for each virtual link
• C. OSPF interface
• D. Area for each range

On an NBMA network, OSPF cannot automatically discover neighbors because the network does not support broadcast or multicast. You must manually specify neighbor IP addresses so OSPF can establish adjacencies and exchange routing information. Without this, OSPF routers on NBMA networks will not form neighbor relationships.

• A. Hybrid routing protocol
• B. Link state routing protocol Correct answer
• C. Distance vector routing protocol

OSPF is a link state routing protocol because it maintains a complete map of the network topology by exchanging link state advertisements (LSAs) with other routers. Each OSPF router independently calculates the shortest path to every destination using Dijkstra's algorithm based on this topology database. This approach allows for faster convergence and more accurate routing decisions compared to distance vector protocols.

• A. True Correct answer
• B. False

OSPF requires a backbone area (Area 0) only when you have multiple areas that need to communicate. If your OSPF deployment has just one area, it can be any area number, and there is no technical requirement for it to be Area 0. The backbone area is essential for inter-area routing, but not for single-area OSPF networks.

• A. True Correct answer
• B. False

A stub area by definition blocks all Type 5 external LSAs from entering. Since an ASBR generates Type 5 LSAs to advertise redistributed external routes, placing an ASBR in a stub area would violate this rule. NSSA areas exist specifically to allow external route origination (as Type 7 LSAs) within a stub-like area.