Foundational networking knowledge across switching, routing, IP services, security, and automation for the Cisco CCNA 200-301 exam, with a worked explanation on every practice question.
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lock_openFree sampleNetwork Fundamentalshard
A host is automatically configuring a link-local IPv6 address with no router present on the segment. Which prefix identifies the address it generates, and what is the defining property of that address?
- Afe80::/10, valid only on the local link and never forwarded by a routercheck_circle Correct
- Bfc00::/7, routable within a single organisation but not on the public internet
- C2000::/3, globally routable and reachable across the public internet
- Dff00::/8, delivered to every interface that has joined the group
Identify the fe80::/10 link-local prefix and recognise that link-local traffic is never forwarded beyond the local link. Every IPv6 interface generates a link-local address from fe80::/10 for on-link functions such as neighbour discovery, and routers are required never to forward packets whose source or destination is link-local, so the address scope is exactly one link.
Why A is correct: Link-local addresses always come from the fe80::/10 range and an IPv6 router never forwards them off the link, so they remain confined to the local segment - this is the defining property the question asks for.
Why B is wrong: fc00::/7 is the unique local address (ULA) range, which is site-scoped and can be routed between internal subnets; it is not the prefix a host self-assigns for link-local communication, so it is the wrong classification here.
Why C is wrong: 2000::/3 is the global unicast range used for internet-reachable addresses; a host cannot mint a globally routable address without a router advertisement supplying the prefix, so this does not describe the no-router self-configured address.
Why D is wrong: ff00::/8 is the multicast range used for one-to-many delivery, not a unicast address a single host assigns to its own interface; it is a tempting confusion because both are auto-derived, but it is not link-local.
lock_openFree sampleNetwork Fundamentalshard
An interface with MAC address 00:1C:2D:AA:BB:CC builds its 64-bit interface identifier using modified EUI-64. Which interface identifier results?
- A001C:2DFF:FEAA:BBCC, splitting the MAC and inserting FFFE with the first octet unchanged
- B021C:2DFF:FEAA:BBCC, splitting the MAC, inserting FFFE, and flipping the seventh bit of the first octetcheck_circle Correct
- C001C:2DFE:FFAA:BBCC, inserting the bytes FEFF in the middle and leaving the first octet unchanged
- D031C:2DFF:FEAA:BBCC, inserting FFFE and flipping the eighth bit of the first octet
Derive a modified EUI-64 interface identifier by splitting the MAC, inserting FFFE, and inverting the seventh bit of the first octet. Modified EUI-64 takes the 48-bit MAC, divides it after the 24-bit OUI, inserts the 16-bit value FFFE, then flips the seventh bit (the universal/local bit) of the first octet, so 00 becomes 02 and the identifier is 021C:2DFF:FEAA:BBCC.
Why A is wrong: This correctly splits the MAC and inserts FFFE in the middle but skips flipping the universal/local bit, leaving the first octet as 00 instead of 02; that omitted bit-flip is the single most common modified EUI-64 mistake.
Why B is correct: Modified EUI-64 splits the OUI from the device portion, inserts FFFE between them, and inverts the seventh bit of the first octet (00 becomes 02), producing exactly 021C:2DFF:FEAA:BBCC.
Why C is wrong: The inserted value is FFFE, not FEFF; reversing those two bytes is a plausible slip but yields an invalid interface identifier, and this answer also fails to flip the universal/local bit.
Why D is wrong: The bit that modified EUI-64 inverts is the seventh bit, not the eighth; flipping the wrong bit turns 00 into 01 rather than 02, so 031C is wrong and so is the stated bit position.
lock_openFree sampleNetwork Fundamentalshard
An engineer must write the address 2001:0DB8:0000:0000:00AB:0000:0000:1234 in its shortest valid form. Which representation is correct?
- A2001:DB8:0:0:AB:0:0:1234
- B2001:DB8:0:0:AB::1234
- C2001:DB8::AB:0:0:1234check_circle Correct
- D2001:DB8::AB::1234
Apply IPv6 text rules: drop leading zeros and use a single :: that collapses the longest, or first equal-length, run of zero groups. IPv6 compression drops leading zeros within each group and permits :: only once, replacing the longest run of all-zero groups; when two runs tie in length the first is collapsed, so the address shortens to 2001:DB8::AB:0:0:1234.
Why A is wrong: This correctly drops the leading zeros in every group but never applies :: at all, so although it is a legal address it is not the shortest form the stem demands; a candidate who forgets that zero-run compression is required would stop here.
Why B is wrong: Here :: replaces the second run of zeros, but both zero runs are two groups long and equal length, so the rule requires collapsing the first run, not the second; choosing the later run is a valid-looking but incorrect placement.
Why C is correct: Leading zeros are dropped in every group and the longest zero run is replaced by ::; the two zero runs are equal length, so :: collapses the first one, giving 2001:DB8::AB:0:0:1234 as the single shortest legal form.
Why D is wrong: Using :: twice is illegal because it makes the address ambiguous about how many zero groups each :: represents, so an address may contain the :: symbol at most once; this is the classic double-:: mistake.
Frequently asked questions
- How many questions are on the 200-301 exam?
- The Cisco Certified Network Associate (CCNA 200-301) (200-301) exam has 100 to 120 questions and runs for 120 minutes. The format is multiple choice, drag-and-drop, and simulation.
- What score do I need to pass 200-301?
- Cisco does not publish a fixed pass mark for 200-301, so treat any "X%" figure you see elsewhere as unofficial. Examworthy gives you a per-domain readiness score so you can judge when you are ready across every domain.
- How much does the 200-301 exam cost?
- The exam costs 300 USD to sit. Practising on Examworthy is free to start, with a worked explanation on every question.
- How does Examworthy help me prepare for 200-301?
- Every practice question carries a worked explanation and a per-distractor rationale, mapped to the official blueprint domains. You learn why each answer is right or wrong, not just the letter.
- Is Examworthy affiliated with Cisco?
- No. Examworthy is not affiliated with or endorsed by Cisco. Our questions are original, blueprint-aligned practice material; we never reproduce live exam items.
Examworthy is not affiliated with or endorsed by Cisco. All questions are original, blueprint-aligned practice material. We never reproduce live exam items. 200-301 and related marks belong to their respective owners.
